Ectoplasm is a Pro Hero and Teacher at UA. His quirk, Clones, allows him to make copies of himself. This quirk is incredibly useful in combat and for supervision around the school.
Ectoplasms has two Enhance abilties. The first Enhance ability is only playable once per turn and requires you to remove a copy of Ectoplasm from your stage. It then makes it so the current attack is considered completely blocked during the Block Step. This is a free automatic block up to three times per game. All you have to do is keep throwing your clones into your rival's attacks.
His second Enhance is also only playable once per turn but it requires you to destroy a foundation as part of its cost. It then allows you to add a copy of the current attack to your hand from your discard pile. This lets you duplicate your attack once per turn!