Necrotic Hydra

Necrotic Hydra enters the battlefield with X
+1/+1 counters on it.
Delve (You may exile any number of cards from
your graveyard as you cast this spell. It costs {1} less
to cast for each card exiled this way.)
"These monstrous fiends rise from battlefields. It's said
that the bloodier the battle, the more heads it has."