Didact Echo is a common Creature — Spirit Cleric card from The Lost Caverns of Ixalan (LCI), collector number 53. Current market price: $0.07 (foil $0.06), TCGplayer market prices via Scryfall.
When this creature enters, draw a card. Descend 4 — This creature has flying as long as there are four or more permanent cards in your graveyard.