Rageborn Muse

Menace, Mountainwalk
Whenever a nonbasic land enters the battlefield
under an opponents control, choose one:
• Rageborn Muse deals 3 damage to that player,
or a creature or planeswalker that player controls.
• Exile the top card of that players library. Until
the end of your next turn, you may play that card
and use mana of any color to cast that spell.