Info on the move Leech Seed

Leech Seed

Move data

Type	grass
Category	Status
Power	0
Accuracy	90
PP	10
Introduced	Generation 1

Leech Seed plants a seed on the target that drains 1⁄8 of its maximum HP at the end of each turn and restores it to the user, or any Pokémon that takes its place. It does not work on Grass-type Pokémon; it does technically work against Pokémon with the Magic Guard ability, but no HP will be sapped.

If the user is holding a Big Root, the move still saps the same amount of HP but recovers 30% more than normal. For example, if a Pokémon has 320 HP, Leech Seed would cause them to lose 40 HP each turn but the seeder would recover 52 HP.

If used on a Pokémon with the ability Liquid Ooze, the user instead loses the HP it would have otherwise gained. The seeded Pokémon can clear Leech Seed by switching out or using Rapid Spin.

When a Pokémon is holding Grassium Z and uses its Z-Power, Leech Seed turns into Z-Leech Seed and eliminates any stat drops applied to the user, in addition to its usual effect as above.

Game descriptions

Gold Silver Crystal	Steals HP from the foe on every turn.
Ruby Sapphire Emerald	Plants a seed on the foe to steal HP on every turn.
FireRed LeafGreen	A seed is planted on the foe to steal some HP for the user on every turn.
Diamond Pearl Platinum HeartGold SoulSilver	A seed is planted on the foe. It steals some HP from the foe to heal the user on every turn.
Black White Black 2 White 2	A seed is planted on the target. It steals some HP from the target every turn.
X Y O.Ruby A.Sapphire	A seed is planted on the target. It steals some HP from the target every turn.
Sun Moon Ultra Sun Ultra Moon L.G. Pikachu L.G. Eevee	A seed is planted on the target. It steals some HP from the target every turn.
Sword Shield B.Diamond S.Pearl	A seed is planted on the target. It steals some HP from the target every turn.