Chipp Zanuff, President Ninja

Commander ninjutsu {u}{b} ({u}{b}, Return
an unblocked attacker you control to hand
Put this card onto the battlefield from your hand or
the command zone tapped and attacking.)

Whenever a Ninja you control deals combat damage
to a player, reveal the top card of your lbrary and
put that card into your hand. Each opponent loses
life equal to that cards mana value.