Curse of the Steed

Beguile {2}{b} (If this card is untapped, when a creature attacks you or a planeswalker you control, you may pay {2}{b}. If you do, attach this card to that creature's controller. It becomes an Aura Curse.)
If Curse of the Steed is attached to a player, it gains "{3}{b}: Until end of turn, creatures enchanted player controls lose all abilities and becomes black Horses with base power and toughness 3/3."