Nihilum, Terror of Amonkhet

Nihilum, Terror of Amonkhet enters the battlefield with a -1/-1 counter on it for each
creature in your graveyard.
{ut}, Discard a card: Target creature gets -X/-X
until end of turn, where X is the number of
counters on Nihilum, Terror of Amonkhet.
Affinity for Zombies (This spell costs {1} less to cast
for each Zombie you control.)