Essence Channeler is a rare Creature — Bat Cleric card from Bloomburrow (BLB), collector number 356. Current market price: $1.73 (foil $2.57), TCGplayer market prices via Scryfall.
As long as you've lost life this turn, this creature has flying and vigilance. Whenever you gain life, put a +1/+1 counter on this creature. When this creature dies, put its counters on target creature you control.