I tried to test out a Ricochet/Cremation/Black Cat deck when I found out that playing Cremation on a Black Cat freezes the game. Also, if you play Cremation on another creature and it ricochets to a Black Cat, it doesn't freeze the game, but the game lets you use that Cremation again.
EDIT: Ricochet'd Cremations also just kill the Black Cat without regard for its multiple lives.