diff --git a/data/lib/formes.ts b/data/lib/formes.ts
new file mode 100644
index 00000000..365407ed
--- /dev/null
+++ b/data/lib/formes.ts
@@ -0,0 +1,418 @@
+// Generated by tools/spritedata/formes.ts; do not edit.
+// Each forme's published name -> the name it falls back on for art.
+
+export const FORME_PARENTS: Record<string, string> = {
+    'venusaur-mega': 'venusaur',
+    'charizard-mega-x': 'charizard',
+    'charizard-mega-y': 'charizard',
+    'blastoise-mega': 'blastoise',
+    'beedrill-mega': 'beedrill',
+    'pidgeot-mega': 'pidgeot',
+    'rattata-alola': 'rattata',
+    'raticate-alola': 'raticate',
+    'raticate-alola-totem': 'raticate-alola',
+    'pikachu-original': 'pikachu',
+    'pikachu-hoenn': 'pikachu',
+    'pikachu-sinnoh': 'pikachu',
+    'pikachu-unova': 'pikachu',
+    'pikachu-kalos': 'pikachu',
+    'pikachu-alola': 'pikachu',
+    'pikachu-partner': 'pikachu',
+    'pikachu-starter': 'pikachu',
+    'pikachu-world': 'pikachu',
+    'pikachu-rock-star': 'pikachu',
+    'pikachu-belle': 'pikachu',
+    'pikachu-pop-star': 'pikachu',
+    'pikachu-phd': 'pikachu',
+    'pikachu-libre': 'pikachu',
+    'pikachu-cosplay': 'pikachu',
+    'raichu-alola': 'raichu',
+    'raichu-mega-x': 'raichu',
+    'raichu-mega-y': 'raichu',
+    'sandshrew-alola': 'sandshrew',
+    'sandslash-alola': 'sandslash',
+    'clefable-mega': 'clefable',
+    'vulpix-alola': 'vulpix',
+    'ninetales-alola': 'ninetales',
+    'diglett-alola': 'diglett',
+    'dugtrio-alola': 'dugtrio',
+    'meowth-alola': 'meowth',
+    'meowth-galar': 'meowth',
+    'persian-alola': 'persian',
+    'growlithe-hisui': 'growlithe',
+    'arcanine-hisui': 'arcanine',
+    'alakazam-mega': 'alakazam',
+    'victreebel-mega': 'victreebel',
+    'geodude-alola': 'geodude',
+    'graveler-alola': 'graveler',
+    'golem-alola': 'golem',
+    'ponyta-galar': 'ponyta',
+    'rapidash-galar': 'rapidash',
+    'slowpoke-galar': 'slowpoke',
+    'slowbro-mega': 'slowbro',
+    'slowbro-galar': 'slowbro',
+    'farfetchd-galar': 'farfetchd',
+    'grimer-alola': 'grimer',
+    'muk-alola': 'muk',
+    'gengar-mega': 'gengar',
+    'voltorb-hisui': 'voltorb',
+    'electrode-hisui': 'electrode',
+    'exeggutor-alola': 'exeggutor',
+    'marowak-alola': 'marowak',
+    'marowak-alola-totem': 'marowak-alola',
+    'weezing-galar': 'weezing',
+    'kangaskhan-mega': 'kangaskhan',
+    'starmie-mega': 'starmie',
+    'mr-mime-galar': 'mr-mime',
+    'pinsir-mega': 'pinsir',
+    'tauros-paldea-combat': 'tauros',
+    'tauros-paldea-blaze': 'tauros',
+    'tauros-paldea-aqua': 'tauros',
+    'gyarados-mega': 'gyarados',
+    'eevee-starter': 'eevee',
+    'aerodactyl-mega': 'aerodactyl',
+    'articuno-galar': 'articuno',
+    'zapdos-galar': 'zapdos',
+    'moltres-galar': 'moltres',
+    'dragonite-mega': 'dragonite',
+    'mewtwo-mega-x': 'mewtwo',
+    'mewtwo-mega-y': 'mewtwo',
+    'meganium-mega': 'meganium',
+    'typhlosion-hisui': 'typhlosion',
+    'feraligatr-mega': 'feraligatr',
+    'pichu-spiky-eared': 'pichu',
+    'ampharos-mega': 'ampharos',
+    'wooper-paldea': 'wooper',
+    'slowking-galar': 'slowking',
+    'unown-b': 'unown',
+    'unown-c': 'unown',
+    'unown-d': 'unown',
+    'unown-e': 'unown',
+    'unown-f': 'unown',
+    'unown-g': 'unown',
+    'unown-h': 'unown',
+    'unown-i': 'unown',
+    'unown-j': 'unown',
+    'unown-k': 'unown',
+    'unown-l': 'unown',
+    'unown-m': 'unown',
+    'unown-n': 'unown',
+    'unown-o': 'unown',
+    'unown-p': 'unown',
+    'unown-q': 'unown',
+    'unown-r': 'unown',
+    'unown-s': 'unown',
+    'unown-t': 'unown',
+    'unown-u': 'unown',
+    'unown-v': 'unown',
+    'unown-w': 'unown',
+    'unown-x': 'unown',
+    'unown-y': 'unown',
+    'unown-z': 'unown',
+    'unown-exclamation': 'unown',
+    'unown-question': 'unown',
+    'steelix-mega': 'steelix',
+    'qwilfish-hisui': 'qwilfish',
+    'scizor-mega': 'scizor',
+    'heracross-mega': 'heracross',
+    'sneasel-hisui': 'sneasel',
+    'corsola-galar': 'corsola',
+    'skarmory-mega': 'skarmory',
+    'houndoom-mega': 'houndoom',
+    'tyranitar-mega': 'tyranitar',
+    'sceptile-mega': 'sceptile',
+    'blaziken-mega': 'blaziken',
+    'swampert-mega': 'swampert',
+    'zigzagoon-galar': 'zigzagoon',
+    'linoone-galar': 'linoone',
+    'gardevoir-mega': 'gardevoir',
+    'sableye-mega': 'sableye',
+    'mawile-mega': 'mawile',
+    'aggron-mega': 'aggron',
+    'medicham-mega': 'medicham',
+    'manectric-mega': 'manectric',
+    'sharpedo-mega': 'sharpedo',
+    'camerupt-mega': 'camerupt',
+    'altaria-mega': 'altaria',
+    'castform-sunny': 'castform',
+    'castform-rainy': 'castform',
+    'castform-snowy': 'castform',
+    'banette-mega': 'banette',
+    'chimecho-mega': 'chimecho',
+    'absol-mega': 'absol',
+    'absol-mega-z': 'absol-mega',
+    'glalie-mega': 'glalie',
+    'salamence-mega': 'salamence',
+    'metagross-mega': 'metagross',
+    'latias-mega': 'latias',
+    'latios-mega': 'latios',
+    'kyogre-primal': 'kyogre',
+    'groudon-primal': 'groudon',
+    'rayquaza-mega': 'rayquaza',
+    'deoxys-attack': 'deoxys',
+    'deoxys-defense': 'deoxys',
+    'deoxys-speed': 'deoxys',
+    'staraptor-mega': 'staraptor',
+    'burmy-sandy': 'burmy',
+    'burmy-trash': 'burmy',
+    'wormadam-sandy': 'wormadam',
+    'wormadam-trash': 'wormadam',
+    'cherrim-sunshine': 'cherrim',
+    'shellos-east': 'shellos',
+    'gastrodon-east': 'gastrodon',
+    'lopunny-mega': 'lopunny',
+    'garchomp-mega': 'garchomp',
+    'garchomp-mega-z': 'garchomp-mega',
+    'lucario-mega': 'lucario',
+    'lucario-mega-z': 'lucario-mega',
+    'abomasnow-mega': 'abomasnow',
+    'gallade-mega': 'gallade',
+    'froslass-mega': 'froslass',
+    'rotom-heat': 'rotom',
+    'rotom-wash': 'rotom',
+    'rotom-frost': 'rotom',
+    'rotom-fan': 'rotom',
+    'rotom-mow': 'rotom',
+    'dialga-origin': 'dialga',
+    'palkia-origin': 'palkia',
+    'heatran-mega': 'heatran',
+    'giratina-origin': 'giratina',
+    'darkrai-mega': 'darkrai',
+    'shaymin-sky': 'shaymin',
+    'arceus-fighting': 'arceus',
+    'arceus-flying': 'arceus',
+    'arceus-poison': 'arceus',
+    'arceus-ground': 'arceus',
+    'arceus-rock': 'arceus',
+    'arceus-bug': 'arceus',
+    'arceus-ghost': 'arceus',
+    'arceus-steel': 'arceus',
+    'arceus-fire': 'arceus',
+    'arceus-water': 'arceus',
+    'arceus-grass': 'arceus',
+    'arceus-electric': 'arceus',
+    'arceus-psychic': 'arceus',
+    'arceus-ice': 'arceus',
+    'arceus-dragon': 'arceus',
+    'arceus-dark': 'arceus',
+    'arceus-fairy': 'arceus',
+    'emboar-mega': 'emboar',
+    'samurott-hisui': 'samurott',
+    'excadrill-mega': 'excadrill',
+    'audino-mega': 'audino',
+    'scolipede-mega': 'scolipede',
+    'lilligant-hisui': 'lilligant',
+    'basculin-blue-striped': 'basculin',
+    'basculin-white-striped': 'basculin',
+    'darumaka-galar': 'darumaka',
+    'darmanitan-zen': 'darmanitan',
+    'darmanitan-galar': 'darmanitan',
+    'darmanitan-galar-zen': 'darmanitan-galar',
+    'scrafty-mega': 'scrafty',
+    'yamask-galar': 'yamask',
+    'zorua-hisui': 'zorua',
+    'zoroark-hisui': 'zoroark',
+    'deerling-summer': 'deerling',
+    'deerling-autumn': 'deerling',
+    'deerling-winter': 'deerling',
+    'sawsbuck-summer': 'sawsbuck',
+    'sawsbuck-autumn': 'sawsbuck',
+    'sawsbuck-winter': 'sawsbuck',
+    'eelektross-mega': 'eelektross',
+    'chandelure-mega': 'chandelure',
+    'stunfisk-galar': 'stunfisk',
+    'golurk-mega': 'golurk',
+    'braviary-hisui': 'braviary',
+    'tornadus-therian': 'tornadus',
+    'thundurus-therian': 'thundurus',
+    'landorus-therian': 'landorus',
+    'kyurem-white': 'kyurem',
+    'kyurem-black': 'kyurem',
+    'keldeo-resolute': 'keldeo',
+    'meloetta-pirouette': 'meloetta',
+    'genesect-douse': 'genesect',
+    'genesect-shock': 'genesect',
+    'genesect-burn': 'genesect',
+    'genesect-chill': 'genesect',
+    'chesnaught-mega': 'chesnaught',
+    'delphox-mega': 'delphox',
+    'greninja-bond': 'greninja',
+    'greninja-ash': 'greninja',
+    'greninja-mega': 'greninja',
+    'vivillon-icy-snow': 'vivillon',
+    'vivillon-polar': 'vivillon',
+    'vivillon-tundra': 'vivillon',
+    'vivillon-continental': 'vivillon',
+    'vivillon-garden': 'vivillon',
+    'vivillon-elegant': 'vivillon',
+    'vivillon-modern': 'vivillon',
+    'vivillon-marine': 'vivillon',
+    'vivillon-archipelago': 'vivillon',
+    'vivillon-high-plains': 'vivillon',
+    'vivillon-sandstorm': 'vivillon',
+    'vivillon-river': 'vivillon',
+    'vivillon-monsoon': 'vivillon',
+    'vivillon-savanna': 'vivillon',
+    'vivillon-sun': 'vivillon',
+    'vivillon-ocean': 'vivillon',
+    'vivillon-jungle': 'vivillon',
+    'vivillon-fancy': 'vivillon',
+    'vivillon-pokeball': 'vivillon',
+    'pyroar-mega': 'pyroar',
+    'flabebe-yellow': 'flabebe',
+    'flabebe-orange': 'flabebe',
+    'flabebe-blue': 'flabebe',
+    'flabebe-white': 'flabebe',
+    'floette-yellow': 'floette',
+    'floette-orange': 'floette',
+    'floette-blue': 'floette',
+    'floette-white': 'floette',
+    'floette-eternal': 'floette',
+    'floette-mega': 'floette',
+    'florges-yellow': 'florges',
+    'florges-orange': 'florges',
+    'florges-blue': 'florges',
+    'florges-white': 'florges',
+    'furfrou-heart': 'furfrou',
+    'furfrou-star': 'furfrou',
+    'furfrou-diamond': 'furfrou',
+    'furfrou-debutante': 'furfrou',
+    'furfrou-matron': 'furfrou',
+    'furfrou-dandy': 'furfrou',
+    'furfrou-la-reine': 'furfrou',
+    'furfrou-kabuki': 'furfrou',
+    'furfrou-pharaoh': 'furfrou',
+    'meowstic-f': 'meowstic',
+    'meowstic-m-mega': 'meowstic',
+    'meowstic-f-mega': 'meowstic-f',
+    'aegislash-blade': 'aegislash',
+    'malamar-mega': 'malamar',
+    'barbaracle-mega': 'barbaracle',
+    'dragalge-mega': 'dragalge',
+    'hawlucha-mega': 'hawlucha',
+    'sliggoo-hisui': 'sliggoo',
+    'goodra-hisui': 'goodra',
+    'pumpkaboo-small': 'pumpkaboo',
+    'pumpkaboo-large': 'pumpkaboo',
+    'pumpkaboo-super': 'pumpkaboo',
+    'gourgeist-small': 'gourgeist',
+    'gourgeist-large': 'gourgeist',
+    'gourgeist-super': 'gourgeist',
+    'avalugg-hisui': 'avalugg',
+    'xerneas-neutral': 'xerneas',
+    'zygarde-10': 'zygarde',
+    'zygarde-complete': 'zygarde',
+    'zygarde-mega': 'zygarde',
+    'diancie-mega': 'diancie',
+    'hoopa-unbound': 'hoopa',
+    'decidueye-hisui': 'decidueye',
+    'gumshoos-totem': 'gumshoos',
+    'vikavolt-totem': 'vikavolt',
+    'crabominable-mega': 'crabominable',
+    'oricorio-pom-pom': 'oricorio',
+    'oricorio-pau': 'oricorio',
+    'oricorio-sensu': 'oricorio',
+    'ribombee-totem': 'ribombee',
+    'rockruff-dusk': 'rockruff',
+    'lycanroc-midnight': 'lycanroc',
+    'lycanroc-dusk': 'lycanroc',
+    'wishiwashi-school': 'wishiwashi',
+    'araquanid-totem': 'araquanid',
+    'lurantis-totem': 'lurantis',
+    'salazzle-totem': 'salazzle',
+    'golisopod-mega': 'golisopod',
+    'silvally-fighting': 'silvally',
+    'silvally-flying': 'silvally',
+    'silvally-poison': 'silvally',
+    'silvally-ground': 'silvally',
+    'silvally-rock': 'silvally',
+    'silvally-bug': 'silvally',
+    'silvally-ghost': 'silvally',
+    'silvally-steel': 'silvally',
+    'silvally-fire': 'silvally',
+    'silvally-water': 'silvally',
+    'silvally-grass': 'silvally',
+    'silvally-electric': 'silvally',
+    'silvally-psychic': 'silvally',
+    'silvally-ice': 'silvally',
+    'silvally-dragon': 'silvally',
+    'silvally-dark': 'silvally',
+    'silvally-fairy': 'silvally',
+    'minior-meteor': 'minior',
+    'minior-orange': 'minior',
+    'minior-yellow': 'minior',
+    'minior-green': 'minior',
+    'minior-blue': 'minior',
+    'minior-indigo': 'minior',
+    'minior-violet': 'minior',
+    'togedemaru-totem': 'togedemaru',
+    'mimikyu-busted': 'mimikyu',
+    'mimikyu-totem': 'mimikyu',
+    'mimikyu-busted-totem': 'mimikyu-busted',
+    'drampa-mega': 'drampa',
+    'kommo-o-totem': 'kommo-o',
+    'necrozma-dusk-mane': 'necrozma',
+    'necrozma-dawn-wings': 'necrozma',
+    'necrozma-ultra': 'necrozma',
+    'magearna-original': 'magearna',
+    'magearna-mega': 'magearna',
+    'magearna-original-mega': 'magearna-original',
+    'zeraora-mega': 'zeraora',
+    'cramorant-gulping': 'cramorant',
+    'cramorant-gorging': 'cramorant',
+    'toxtricity-low-key': 'toxtricity',
+    'sinistea-antique': 'sinistea',
+    'polteageist-antique': 'polteageist',
+    'alcremie-ruby-cream': 'alcremie',
+    'alcremie-matcha-cream': 'alcremie',
+    'alcremie-mint-cream': 'alcremie',
+    'alcremie-lemon-cream': 'alcremie',
+    'alcremie-salted-cream': 'alcremie',
+    'alcremie-ruby-swirl': 'alcremie',
+    'alcremie-caramel-swirl': 'alcremie',
+    'alcremie-rainbow-swirl': 'alcremie',
+    'falinks-mega': 'falinks',
+    'eiscue-noice': 'eiscue',
+    'indeedee-f': 'indeedee',
+    'morpeko-hangry': 'morpeko',
+    'zacian-crowned': 'zacian',
+    'zamazenta-crowned': 'zamazenta',
+    'eternatus-eternamax': 'eternatus',
+    'urshifu-rapid-strike': 'urshifu',
+    'zarude-dada': 'zarude',
+    'calyrex-ice': 'calyrex',
+    'calyrex-shadow': 'calyrex',
+    'ursaluna-bloodmoon': 'ursaluna',
+    'basculegion-f': 'basculegion',
+    'enamorus-therian': 'enamorus',
+    'oinkologne-f': 'oinkologne',
+    'maushold-four': 'maushold',
+    'squawkabilly-blue': 'squawkabilly',
+    'squawkabilly-yellow': 'squawkabilly',
+    'squawkabilly-white': 'squawkabilly',
+    'scovillain-mega': 'scovillain',
+    'palafin-hero': 'palafin',
+    'glimmora-mega': 'glimmora',
+    'tatsugiri-droopy': 'tatsugiri',
+    'tatsugiri-stretchy': 'tatsugiri',
+    'tatsugiri-curly-mega': 'tatsugiri',
+    'tatsugiri-droopy-mega': 'tatsugiri-droopy',
+    'tatsugiri-stretchy-mega': 'tatsugiri-stretchy',
+    'dudunsparce-three-segment': 'dudunsparce',
+    'baxcalibur-mega': 'baxcalibur',
+    'gimmighoul-roaming': 'gimmighoul',
+    'poltchageist-artisan': 'poltchageist',
+    'sinistcha-masterpiece': 'sinistcha',
+    'ogerpon-wellspring': 'ogerpon',
+    'ogerpon-hearthflame': 'ogerpon',
+    'ogerpon-cornerstone': 'ogerpon',
+    'ogerpon-teal-tera': 'ogerpon',
+    'ogerpon-wellspring-tera': 'ogerpon-wellspring',
+    'ogerpon-hearthflame-tera': 'ogerpon-hearthflame',
+    'ogerpon-cornerstone-tera': 'ogerpon-cornerstone',
+    'terapagos-terastal': 'terapagos',
+    'terapagos-stellar': 'terapagos',
+    'crucibelle-mega': 'crucibelle',
+    'venomicon-epilogue': 'venomicon',
+    'ramnarok-radiant': 'ramnarok',
+};
diff --git a/smogon.build.ts b/smogon.build.ts
index e614834e..91259e7f 100644
--- a/smogon.build.ts
+++ b/smogon.build.ts
@@ -1,4 +1,6 @@
 
+import {FORME_PARENTS} from '@smogon/sprite-data/formes.ts';
+
 import {gen10Modelslike} from './rules/modelslike.ts';
 import {type Sprite, publishedNames} from './rules/publish.ts';
 import {forEachRule} from './tools/build/artifact.ts';
@@ -75,8 +77,31 @@ let xyIcons = forEachRule('src/minisprites/pokemon/gen6/*.png', {
 }, '%b');
 
 deploy(ctx => {
+    let byName = new Map<string, Sprite>();
     for (let f of xyIcons) {
-        smogonSpritecopy(ctx, f, 'xyicons', publishedNames(f));
+        for (let name of publishedNames(f)) {
+            byName.set(name, f);
+        }
+    }
+    // The games drew no icon for some formes, so PS's own sheet sends them to
+    // the nearest one that has art: Gourgeist-Super to Gourgeist,
+    // Mimikyu-Busted-Totem to Mimikyu-Busted and on to Mimikyu. Walk the same
+    // chain, so a name the data knows gets an icon rather than a 404. Only
+    // this set needs it, since xy/ has real art for every one of them.
+    for (let name of Object.keys(FORME_PARENTS)) {
+        if (byName.has(name)) {
+            continue;
+        }
+        for (let p = FORME_PARENTS[name]; p !== undefined; p = FORME_PARENTS[p]) {
+            let f = byName.get(p);
+            if (f) {
+                byName.set(name, f);
+                break;
+            }
+        }
+    }
+    for (let [name, f] of byName) {
+        smogonSpritecopy(ctx, f, 'xyicons', [name]);
     }
 });
 
diff --git a/tools/spritedata/formes.ts b/tools/spritedata/formes.ts
new file mode 100644
index 00000000..1e6b7f55
--- /dev/null
+++ b/tools/spritedata/formes.ts
@@ -0,0 +1,79 @@
+import {encode, publishedName, smogon} from '@smogon/sprite-data/index.ts';
+
+import {species} from './pokedex.ts';
+
+// Regenerates data/lib/formes.ts from a pokemon-showdown checkout:
+//
+//   node tools/spritedata/formes.ts ~/smogon/pokemon-showdown > data/lib/formes.ts
+//
+// The games drew some formes no art of their own, and a set that has none
+// falls back on the nearest forme it is a refinement of, up to the base
+// species: PS's own icon sheet points Gourgeist-Super at Gourgeist's slot and
+// Mimikyu-Busted-Totem at Mimikyu's. That chain can't be recovered from a
+// published name alone, since a base name carries dashes too (kommo-o,
+// mr-mime, porygon-z), so it is written down here.
+//
+// The parent is the longest run of leading words that names a forme of its
+// own, and the base species otherwise. Dropping one word blindly would strand
+// Toxtricity-Low-Key on a Toxtricity-Low that does not exist.
+
+let ps = process.argv[2];
+if (!ps) {
+    throw new Error('usage: node tools/spritedata/formes.ts <pokemon-showdown checkout>');
+}
+
+// `forme` comes in encoded; `base` does not.
+function published(base: string, forme: string): string {
+    let extra = new Map<string, string>();
+    if (forme) {
+        extra.set('o', forme);
+    }
+    return publishedName({kind: 's', name: encode(base), extra}, smogon);
+}
+
+let all = species(ps);
+
+// Which formes each base species actually has, so a parent can be checked.
+let formes = new Map<string, Set<string>>();
+for (let {base, forme} of all) {
+    let set = formes.get(base);
+    if (!set) {
+        set = new Set();
+        formes.set(base, set);
+    }
+    set.add(encode(forme));
+}
+
+function parent(base: string, forme: string): string {
+    let words = forme.split('_');
+    for (let n = words.length - 1; n > 0; n--) {
+        let shorter = words.slice(0, n).join('_');
+        if (formes.get(base)?.has(shorter)) {
+            return shorter;
+        }
+    }
+    return '';
+}
+
+let out = '';
+out += '// Generated by tools/spritedata/formes.ts; do not edit.\n';
+out += "// Each forme's published name -> the name it falls back on for art.\n\n";
+out += 'export const FORME_PARENTS: Record<string, string> = {\n';
+
+let seen = new Set<string>();
+for (let {base, forme} of all) {
+    if (!forme) {
+        continue;
+    }
+    let name = published(base, encode(forme));
+    // Where formeOrder gives one name to several slots, they share a parent.
+    if (seen.has(name)) {
+        continue;
+    }
+    seen.add(name);
+    out += `    '${name}': '${published(base, parent(base, encode(forme)))}',\n`;
+}
+
+out += '};\n';
+
+process.stdout.write(out);