Nekozawa, the Dark Prince

Skulk (This creature can't be blocked by creatures
with greater power.)
When Nekozawa enters the battlefield, create a
legendary 0/1 black Beelzenef creature token.
Whenever a player casts a black spell, you may
tap Nekozawa. If you do, return target creature
to its owner's hand.
Whenever a player casts a white spell, return
Nekozawa to its owner's hand.