Sirius Black

When Sirius Black enters, you may search your library for a basic Forest card, reveal it, put it into your hand, then shuffle.
Whenever a land you control enters, if you control seven or more lands, exile Sirius, then return him to the battlefield transformed under her owner's control.

We've all got both light and dark inside us. What matters is the part we choose to act on. That's who we really are.