Chal'aga, Spell Glutton

Whenever an opponent casts a spell with converted mana cost equal to the number of +1/+1 counters on Chal'aga, Spell Glutton, counter that spell, then add or remove a +1/+1 counter from Chal'aga, Spell Glutton.
Discard a card: Add or remove a +1/+1 counter from Chal'aga, Spell Glutton.
"And we thought its Spellskite brood were insatiable..." - Malcator, Executor of Synthesis