Defiler of Dreams

Flying As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay. Whenever you cast a blue permanent spell, draw a card.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6o6eih3o5jpb1hnu1a2j29.