Metapod

Harden
During your opponent's next turn, whenever 20 or less damage is done to Metapod (after applying Weakness and Resistance), prevent that damage. (Any other effects of attacks still happen.)

Hatch
Flip a coin. If heads, remove all damage counters from Metapod. Then, search your deck for a card that evolves from Metapod and attach that card to Metapod. This counts as evolving Metapod. Shuffle your deck afterward.