Xeno, Unnourished Bloodblower

Indestructible
Xeno isn't a creature until you've destroyed 4 or
more creatures in one turn or you've destroyed another god or legendary creature.
At any time, you may switch Xeno's colors from
red to black. If Xeno was any color but red when
you or your opponent triggered this ability, turn
Xeno's colors to red instead. Your opponent
loses 6 life.