Corelli, Eternal Joy

Whenever you cast an instant or sorcery spell,
put a +1/+1 counter on Corelli.
At the beginning of your upkeep, remove a
+1/+1 counter from Corelli.
Remove a +1/+1 counter from Corelli: Corelli
gains Hexproof until end of turn.
"A spell a day keeps the boring away!"