Mangara's Equity

As this enchantment enters, choose black or red. At the beginning of your upkeep, sacrifice this enchantment unless you pay {1}{W}. Whenever a creature of the chosen color deals damage to you or a white creature you control, this enchantment deals that much damage to that creature.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6odipp9hx1pb1hipz16j2k.