GC Leaf Guard 30

During your opponent's next turn, any damage done to Tangrowth by attacks is reduced by 20 (after applying Weakness and Resistance).

GGCC Swallow Up 50

Before doing damage, count the remaining HP of the Defending Pokémon and Tangrowth. If the Defending Pokémon has fewer remaining HP than Tangrowth's, this attack does 120 damage instead.