Abhorrent Overlord

Flying When this creature enters, create a number of 1/1 black Harpy creature tokens with flying equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.) At the beginning of your upkeep, sacrifice a creature.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6o9hol67zppb1hvouilt0x.