Gengar

Gengar can't be targeted with abilities or blocked
by creatures with -1/-1 counters on them.
{b}{b}: Put a -1/-1 counter on target creature.
Whenever Gengar deals combat damage to a
player, that player exiles two cards at random.
Should you feel attacked by a sudden chill, it is
evidence of an approaching Gengar. There is no
escaping it. Give up. -Pokedex entry