Mazzy, Truesword Paladin is a rare Legendary Creature — Halfling Knight card from Alchemy Horizons: Baldur's Gate (HBG), collector number 241.
Whenever an enchanted creature attacks one of your opponents, it gets +2/+0 and gains trample until end of turn. Whenever an Aura you control is put into your graveyard from the battlefield, exile it. Until the end of your next turn, you may cast that card.