Beast Boy of Many Forms

When Beast Boy enters the battlefield or attacks,
exile a nonhuman creature card from your hand
or graveyard with a form counter on it.
{g}{u}: Choose a card you own in exile with a form counter on it. Beast Boy becomes a copy of that
card until end of turn, except its name is still
Beast Boy of Many Forms, it's a legendary green Shapeshifter Hero in addition to its other colors
and types, and it has Beast Boy's abilities.