Corpuscarii Electro-priest

Canticle (You may tap this creature. If you do, you
gain 1 counter of Maintenance, then trigger any
relevant Canticle effects. All counters of Maintenance
are sacrificed during the end step.) Once you have 3
or more Maintenance counters, you may discard
an instant or sorcery card from your hand. If you
do, then draw 2 cards.
Whenever you cast an instant or sorcery, untap Corpuscarii Electro-priest. It gets flying
and +2/+0 until end turn.