Return target creature that was placed in your graveyard this turn to play. It is now a beast.
Regeneration means that later this turn, instead of dying and then undying again, you don't die – but it's only that second part that is the actual regeneration, so you can regenerate even if you have been told that you can't, it's just that you don't actually regenerate; even though nothing else works that way. Clear? Oh, and go kill Zeus when you have a moment.
(art)