Gavin Guile, Black Prism

{3}{w}: Gavin Guile, Black Prism deals 4 damage to target attacking or blocking creature.
If Gavin Guile, Black Prism would die, exile him instead, then return him to the battlefield transformed under his owner’s control.

"You might want to think twice before you try to use
a man's conscience against him. It may turn out he doesn't have one."