Black Widow, Super Spy (Borderless) (0393)

Menace
Whenever Black Widow deals combat damage to a player, that player exiles cards from the top of their library until they exile a nonland card. You may put a +1/+1 counter on Black Widow. If you don't, you may cast the exiled nonland card until end of turn and mana of any type can be spent to cast that spell.