Gallius Jack, Nightstalker

Whenever Gallius Jack, Nightstalker deals
combat damage to a player, exile the top card of
each player's library.
Players may cast cards exiled with Gallius Jack
and may spend mana as though it were of any
type to cast them.
Whenever an opponent casts a spell from exile,
put a +1/+1 counter on Gallius Jack.