Keul, Galvanic Instigator

Eminence—Whenever an opponent casts their
first spell during another player's turn, you may
tap target creature that opponent controls and
goad it at the beginning of the next end step.
Haste, basic landwalk, hexproof from lands
{x}, {ut}: Each player reveals the top card of their library and casts it without paying its mana cost
if its mana value is X or less. Exchange control
of two of those spells.