Curse is learned by 55 species by level, 397 by machine and 86 by egg

Effect, in PokéAPI's words

“Ghosts pay half their max HP to hurt the target every turn. Others decrease Speed but raise Attack and Defense.”

Who learns it

427 species in all, 4 of 19 games shown

Scarlet and Violet: 239 species

Species	Method	Level
Slowpoke	Level up, Machine	1
Slowbro	Level up, Machine	1
Slowking	Level up, Machine	1
Chandelure	Level up, Machine	1
Appletun	Level up, Machine	4
Bergmite	Level up, Machine	9
Avalugg	Level up, Machine	9
Golett	Level up, Machine	16
Golurk	Level up, Machine	16
Turtwig	Level up, Machine	17
Grotle	Level up, Machine	17
Torterra	Level up, Machine	17
Gastly	Level up, Machine	20
Haunter	Level up, Machine	20
Gengar	Level up, Machine	20
Pineco	Level up, Machine	23
Forretress	Level up, Machine	23
Shuppet	Level up, Machine	26
Banette	Level up, Machine	26
Numel	Level up, Machine	29
Camerupt	Level up, Machine	29
Regirock	Level up, Machine	30
Regice	Level up, Machine	30
Registeel	Level up, Machine	30
Litwick	Level up, Machine	32
Lampent	Level up, Machine	32
Phantump	Level up, Machine	32
Trevenant	Level up, Machine	32
Pincurchin	Level up, Machine	35
Duskull	Level up, Machine	36
Dusclops	Level up, Machine	36
Dusknoir	Level up, Machine	36
Spiritomb	Level up, Machine	40
Goomy	Level up, Machine	41
Sliggoo	Level up, Machine	43
Goodra	Level up, Machine	43
Torkoal	Level up, Machine	44
Bramblin	Level up, Machine	45
Brambleghast	Level up, Machine	45
Polteageist	Level up, Machine	66
Bulbasaur	Machine, Egg
Ivysaur	Machine, Egg
Venusaur	Machine, Egg
Sandshrew	Machine
Sandslash	Machine
Diglett	Machine
Dugtrio	Machine
Mankey	Machine, Egg
Primeape	Machine
Growlithe	Machine
Arcanine	Machine
Geodude	Machine, Egg
Graveler	Machine, Egg
Golem	Machine, Egg
Seel	Machine
Dewgong	Machine
Grimer	Machine, Egg
Muk	Machine
Drowzee	Machine
Hypno	Machine
Electrode	Machine
Exeggcute	Machine, Egg
Exeggutor	Machine
Koffing	Machine, Egg
Weezing	Machine
Rhyhorn	Machine, Egg
Rhydon	Machine, Egg
Magmar	Machine
Tauros	Machine, Egg
Lapras	Machine, Egg
Eevee	Machine, Egg
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Snorlax	Machine, Egg
Mewtwo	Machine
Mew	Machine
Chikorita	Machine
Bayleef	Machine
Meganium	Machine
Cyndaquil	Machine, Egg
Quilava	Machine, Egg
Typhlosion	Machine, Egg
Totodile	Machine
Croconaw	Machine
Feraligatr	Machine
Noctowl	Machine
Chinchou	Machine
Lanturn	Machine
Sudowoodo	Machine
Sunkern	Machine, Egg
Sunflora	Machine
Wooper	Machine, Egg
Quagsire	Machine
Espeon	Machine
Umbreon	Machine
Misdreavus	Machine, Egg
Dunsparce	Machine, Egg
Snubbull	Machine
Granbull	Machine
Qwilfish	Machine
Scizor	Machine
Heracross	Machine
Slugma	Machine, Egg
Magcargo	Machine, Egg
Swinub	Machine, Egg
Piloswine	Machine, Egg
Skarmory	Machine, Egg
Phanpy	Machine
Donphan	Machine
Stantler	Machine
Magby	Machine
Larvitar	Machine, Egg
Pupitar	Machine
Tyranitar	Machine
Lugia	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Mudkip	Machine, Egg
Marshtomp	Machine, Egg
Swampert	Machine, Egg
Seedot	Machine
Nuzleaf	Machine
Shiftry	Machine
Slakoth	Machine, Egg
Vigoroth	Machine
Slaking	Machine
Hariyama	Machine
Nosepass	Machine
Gulpin	Machine, Egg
Swalot	Machine
Cacnea	Machine
Cacturne	Machine
Zangoose	Machine, Egg
Seviper	Machine
Whiscash	Machine
Tropius	Machine, Egg
Chimecho	Machine, Egg
Cranidos	Machine
Rampardos	Machine
Shieldon	Machine
Bastiodon	Machine
Shellos	Machine, Egg
Gastrodon	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Chingling	Machine, Egg
Bonsly	Machine, Egg
Munchlax	Machine, Egg
Hippopotas	Machine, Egg
Hippowdon	Machine
Snover	Machine
Abomasnow	Machine
Rhyperior	Machine, Egg
Magmortar	Machine
Leafeon	Machine
Glaceon	Machine
Mamoswine	Machine, Egg
Probopass	Machine
Froslass	Machine
Giratina	Machine
Darkrai	Machine
Tepig	Machine
Pignite	Machine
Emboar	Machine
Drilbur	Machine
Excadrill	Machine
Timburr	Machine
Gurdurr	Machine
Conkeldurr	Machine
Sandile	Machine
Krokorok	Machine
Krookodile	Machine
Scraggy	Machine
Scrafty	Machine
Sawsbuck	Machine
Beartic	Machine
Chespin	Machine, Egg
Quilladin	Machine, Egg
Chesnaught	Machine, Egg
Sylveon	Machine
Decidueye	Machine
Gumshoos	Machine
Mudbray	Machine
Mudsdale	Machine
Passimian	Machine
Sandygast	Machine, Egg
Palossand	Machine
Komala	Machine
Mimikyu	Machine, Egg
Skwovet	Machine
Greedent	Machine
Corviknight	Machine
Rolycoly	Machine
Carkol	Machine
Coalossal	Machine
Sinistea	Machine
Perrserker	Machine
Stonjourner	Machine, Egg
Cufant	Machine, Egg
Copperajah	Machine
Dreepy	Machine, Egg
Drakloak	Machine
Dragapult	Machine
Glastrier	Machine
Spectrier	Machine
Wyrdeer	Machine
Ursaluna	Machine
Overqwil	Machine
Fuecoco	Machine, Egg
Crocalor	Machine
Skeledirge	Machine
Lechonk	Machine
Oinkologne	Machine
Nacli	Machine, Egg
Naclstack	Machine
Garganacl	Machine
Ceruledge	Machine
Mabosstiff	Machine
Bombirdier	Machine
Varoom	Machine
Revavroom	Machine
Orthworm	Machine, Egg
Cetoddle	Machine
Cetitan	Machine
Dondozo	Machine, Egg
Annihilape	Machine
Clodsire	Machine
Farigiraf	Machine
Dudunsparce	Machine
Slither Wing	Machine
Iron Thorns	Machine
Poltchageist	Machine
Sinistcha	Machine
Okidogi	Machine
Hydrapple	Machine
Pecharunt	Machine

Brilliant Diamond and Shining Pearl: 71 species

Species	Method	Level
Slowpoke	Level up	1
Slowbro	Level up	1
Slowking	Level up	1
Onix	Level up	16
Steelix	Level up	16
Turtwig	Level up	17
Grotle	Level up	17
Torterra	Level up	17
Gastly	Level up	20
Haunter	Level up	20
Gengar	Level up	20
Shuppet	Level up	26
Banette	Level up	26
Numel	Level up	29
Camerupt	Level up	29
Regirock	Level up	30
Regice	Level up	30
Registeel	Level up	30
Duskull	Level up	36
Dusclops	Level up	36
Dusknoir	Level up	36
Spiritomb	Level up	40
Torkoal	Level up	44
Bidoof	Level up	49
Bibarel	Level up	58
Bulbasaur	Egg
Zubat	Egg
Geodude	Egg
Farfetch’d	Egg
Grimer	Egg
Exeggcute	Egg
Cubone	Egg
Lickitung	Egg
Koffing	Egg
Rhyhorn	Egg
Lapras	Egg
Eevee	Egg
Aerodactyl	Egg
Snorlax	Egg
Sudowoodo	Egg
Sunkern	Egg
Wooper	Egg
Misdreavus	Egg
Dunsparce	Egg
Slugma	Egg
Swinub	Egg
Corsola	Egg
Skarmory	Egg
Miltank	Egg
Larvitar	Egg
Torchic	Egg
Mudkip	Egg
Slakoth	Egg
Aron	Egg
Electrike	Egg
Gulpin	Egg
Wailmer	Egg
Zangoose	Egg
Lileep	Egg
Anorith	Egg
Tropius	Egg
Chimecho	Egg
Absol	Egg
Spheal	Egg
Cranidos	Egg
Shieldon	Egg
Shellos	Egg
Chingling	Egg
Bonsly	Egg
Munchlax	Egg
Hippopotas	Egg

Sword and Shield: 89 species

Species	Method	Level
Slowpoke	Level up	1
Slowbro	Level up	1
Slowking	Level up	1
Chandelure	Level up	1
Accelgor	Level up	1
Appletun	Level up	4
Shelmet	Level up	8
Bergmite	Level up	9
Avalugg	Level up	9
Onix	Level up	16
Steelix	Level up	16
Golett	Level up	16
Golurk	Level up	16
Gastly	Level up	20
Haunter	Level up	20
Gengar	Level up	20
Regirock	Level up	30
Regice	Level up	30
Registeel	Level up	30
Tirtouga	Level up	30
Carracosta	Level up	30
Pyukumuku	Level up	30
Cursola	Level up	30
Litwick	Level up	32
Lampent	Level up	32
Phantump	Level up	32
Trevenant	Level up	32
Pincurchin	Level up	35
Duskull	Level up	36
Dusclops	Level up	36
Dusknoir	Level up	36
Yamask	Level up	36
Cofagrigus	Level up	38
Runerigus	Level up	38
Spiritomb	Level up	40
Ferroseed	Level up	41
Goomy	Level up	41
Ferrothorn	Level up	43
Sliggoo	Level up	43
Goodra	Level up	43
Torkoal	Level up	44
Polteageist	Level up	66
Bulbasaur	Egg
Zubat	Egg
Farfetch’d	Egg
Exeggcute	Egg
Cubone	Egg
Lickitung	Egg
Koffing	Egg
Rhyhorn	Egg
Lapras	Egg
Eevee	Egg
Aerodactyl	Egg
Snorlax	Egg
Sudowoodo	Egg
Wooper	Egg
Dunsparce	Egg
Swinub	Egg
Corsola	Egg
Skarmory	Egg
Miltank	Egg
Larvitar	Egg
Torchic	Egg
Mudkip	Egg
Aron	Egg
Electrike	Egg
Wailmer	Egg
Lileep	Egg
Anorith	Egg
Absol	Egg
Spheal	Egg
Shellos	Egg
Bonsly	Egg
Munchlax	Egg
Hippopotas	Egg
Munna	Egg
Roggenrola	Egg
Dwebble	Egg
Trubbish	Egg
Stunfisk	Egg
Heatmor	Egg
Tyrunt	Egg
Pumpkaboo	Egg
Sandygast	Egg
Turtonator	Egg
Mimikyu	Egg
Stonjourner	Egg
Cufant	Egg
Dreepy	Egg

Ultra Sun and Ultra Moon: 101 species

Species	Method	Level
Slowpoke	Level up	1
Slowbro	Level up	1
Slowking	Level up	1
Spiritomb	Level up	1
Ferrothorn	Level up	1, 9
Onix	Level up	4
Steelix	Level up	4
Ferroseed	Level up	9
Gastly	Level up	12
Haunter	Level up	12
Gengar	Level up	12
Shelmet	Level up	13
Turtwig	Level up	17
Grotle	Level up	17
Torterra	Level up	17
Torkoal	Level up	22
Bergmite	Level up	22
Avalugg	Level up	22
Regirock	Level up	25
Regice	Level up	25
Registeel	Level up	25
Pyukumuku	Level up	25
Shuppet	Level up	26
Banette	Level up	26
Phantump	Level up	28
Trevenant	Level up	28
Numel	Level up	29
Camerupt	Level up	29
Yamask	Level up	29
Cofagrigus	Level up	29
Duskull	Level up	33
Dusclops	Level up	33
Dusknoir	Level up	33
Tirtouga	Level up	35
Carracosta	Level up	35
Litwick	Level up	43
Lampent	Level up	45
Golett	Level up	45
Golurk	Level up	47
Bidoof	Level up	49
Bibarel	Level up	58
Bulbasaur	Egg
Zubat	Egg
Geodude	Egg
Farfetch’d	Egg
Grimer	Egg
Exeggcute	Egg
Cubone	Egg
Lickitung	Egg
Koffing	Egg
Rhyhorn	Egg
Lapras	Egg
Eevee	Egg
Aerodactyl	Egg
Snorlax	Egg
Sudowoodo	Egg
Sunkern	Egg
Wooper	Egg
Misdreavus	Egg
Dunsparce	Egg
Slugma	Egg
Swinub	Egg
Corsola	Egg
Skarmory	Egg
Miltank	Egg
Larvitar	Egg
Torchic	Egg
Mudkip	Egg
Slakoth	Egg
Aron	Egg
Electrike	Egg
Gulpin	Egg
Wailmer	Egg
Zangoose	Egg
Lileep	Egg
Anorith	Egg
Tropius	Egg
Chimecho	Egg
Absol	Egg
Spheal	Egg
Cranidos	Egg
Shieldon	Egg
Shellos	Egg
Chingling	Egg
Bonsly	Egg
Munchlax	Egg
Hippopotas	Egg
Tepig	Egg
Munna	Egg
Roggenrola	Egg
Dwebble	Egg
Trubbish	Egg
Stunfisk	Egg
Heatmor	Egg
Chespin	Egg
Tyrunt	Egg
Goomy	Egg
Pumpkaboo	Egg
Rowlet	Egg
Sandygast	Egg
Mimikyu	Egg

Changed over time

One change since Generation II

1. Through Gen IVType UnknownGhost from Black and White, Generation V