Unnerve (Japanese: きんちょうかんTension) is an Ability introduced in Generation V.
Effect
In battle
Generation V
Unnerve causes opposing Pokémon to be unable to eat their own heldBerries. However, it does not prevent usage of Natural Gift. When an Unnerve user switches in, the Ability displays a message. If there are entry hazards, then they activate after the message.
Foes next to the Pokémon cannot eat or drink.* Foes next to the Pokémon become nervous and can't eat or drink! Thrown items that hit them will still have an effect.*