Pressure

Pressure is an ability introduced in Generation III that deducts double the foe's PP for every successful hit. It still works if the Pokémon is immune to the move used (such as Acid being used on a Steel-type). Outside of battle, if a Pokémon with Pressure is at the front the party, it decreases the chances of battling a higher level Pokémon by 50%.

Twenty-one Pokémon have this ability, fourteen of which are legendary.

In Generation IV, when a Pokémon with this ability enters the battle, the game makes the reference "Name is exerting its Pressure." in the dialog box.

Pokémon

Pokédex	Pokémon	Sprite	Type	Obtained
#142	Aerodactyl			Natural
#144	Articuno			Natural
#145	Zapdos			Natural
#146	Moltres			Natural
#150	Mewtwo			Natural
#243	Raikou			Natural
#244	Entei			Natural
#245	Suicune			Natural
#249	Lugia			Natural
#250	Ho-Oh			Natural
#320	Wailmer			Dream World
#321	Wailord			Dream World
#356	Dusclops			Natural
#359	Absol			Natural
#386	Deoxys			Natural
#416	Vespiquen			Natural
#442	Spiritomb			Natural
#461	Weavile			Natural
#477	Dusknoir			Natural
#483	Dialga			Natural
#484	Palkia			Natural
#487	Giratina			Natural
#624	Pawniard			Dream World
#625	Bisharp			Dream World
#646	Kyurem			Natural

Trivia

• Giratina has Pressure while in its Alternate Form and Levitate while in its Origin Form.
• Absol is the only Pokémon with 2 abilities (not including hidden ones) that has Pressure as its first ability.