First strike (This creature deals combat damage before creatures without first strike.)
When Impetuous Lootmonger enters the battlefield, discard a card, then
heist target opponent's library
(Look at three random nonland cards in target opponent's library and exile one face down. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast it.).
Whenever you cast a spell you don't own, create a
Treasure token
(A Treasure is an artifact with ", Sacrifice this artifact: Add one mana of any color.").