Silent Fang Agent

Ninjutsu {1}{u} ({1}{u}, Return an unblocked attacker
you control to hand: Put this card onto the battlefield
from your hand tapped and attacking.)
Whenever Silent Fang Agent deals combat
damage to a player, another target creature
phases out. (While it's phased out, it's treated as
though it doesn't exist. That creature phases in before
you untap during your untap step.)