Tesla Tower

Defender Evolution 3 (Each time you cast this spell, place an evolution counter on it. Evolution counters stay on cards even when they change zones. When it has 3 evolution counters on it, remove all evolution counters and flip it. If 2 or more cards with Evolution have already been flipped by you, this ability does not function.) {T}: Tesla deals 2 damage to target creature. At the beginning of combat on your turn, untap tesla. While tesla is untapped, it has hexproof.