Laughing Jasper Flint (OTJ #215)

Creatures you control but don’t own are Mercenaries in addition to their other types.

At the beginning of your upkeep, exile the top X cards of target opponent’s library, where X is the number of outlaws you control. Until end of turn, you may cast spells from among those cards, and mana of any type can be spent to cast those spells.