Fae-Crafted Prosthetic

You may pay {2}{b}{b} rather than paying this spell's mana cost. If you do, it enters the battlefield attached to target creature you don't control.
Equipped creature gets +1/-1 and has "Whenever this creature attacks or blocks, discard a card."
{2}{b}: Attach Fae-Crafted Prosthetic to target creature. Activate this ability only any time you could cast a sorcery.