Tyrion, the Imp

Boast - {u/b}: Create a Clue token for each
attacking creature you control.
{1}, Sacrifice a Clue: create a Treasure token.
{x}: Gain control of target creature an opponent
controls until end of turn. That creature gains
haste until end of turn. Only mana from
Treasures can pay for this ability. Any opponent
may negate this ability by paying {x}.