Runeforged Hydra

Runeforged Hydra enters the battlefield with
X +1/+1 counters on it.
Spells you cast cost {1} less to cast for each
+1/+1 counter on Runeforged Hydra.
Whenever you cast a spell, remove a +1/+1 counter from Runeforged Hydra.
1{w/u}{w/u}: Put a +1/+1 counter on Runeforged Hydra.