Insomnia (Japanese: ふみん, Hepburn: Insomnia) is an ability introduced in Generation III.
Effect
The Pokémon cannot be put to sleep; this includes both opponent-induced sleep, as well as user-induced sleep via Rest. If the Pokémon tries to use moves such as Rest, that move will fail. Along with Vital Spirit, it is one of two Abilities that prevent sleeping.
| Generations | Description |
|---|---|
| Generation III | The Pokémon is suffering from insomnia and cannot fall asleep. |
| Generation IV | |
| Generation V | |
| Generation VI | |
| Generation VII | |
| Generation VIII | |
| Generation IX |
Pokémon
| Pokémon | Type | First Ability | Second Ability | Hidden Ability | |
|---|---|---|---|---|---|
 | Drowzee |  Psychic | Insomnia | Forewarn | Inner Focus |
 | Hypno | Psychic | Insomnia | Forewarn | Inner Focus |
 | Mega Mewtwo Y | Psychic | Insomnia | — | — |
 | Hoothoot |  Normal /  Flying | Insomnia | Keen Eye | Tinted Lens |
 | Noctowl | Normal / Flying | Insomnia | Keen Eye | Tinted Lens |
 | Spinarak |  Bug /  Poison | Swarm | Insomnia | Sniper |
 | Ariados | Bug / Poison | Swarm | Insomnia | Sniper |
 | Murkrow |  Dark / Flying | Insomnia | Super Luck | Prankster |
 | Shuppet |  Ghost | Insomnia | Frisk | Cursed Body |
 | Banette | Ghost | Insomnia | Frisk | Cursed Body |
 | Honchkrow | Dark / Flying | Insomnia | Super Luck | Moxie |
 | Tarountula | Bug | Insomnia | — | Stakeout |
 | Spidops | Bug | Insomnia | — | Stakeout |
 | Capsakid |  Grass | Chlorophyll | Insomnia | Klutz |
 | Scovillain | Grass /  Fire | Chlorophyll | Insomnia | Moody |
 | Delibird |  Ice / Flying | Vital Spirit | Hustle | Insomnia |
 | Pumpkaboo | Ghost / Grass | Pickup | Frisk | Insomnia |
 | Gourgeist | Ghost / Grass | Pickup | Frisk | Insomnia |