Yirimus, Thief Trademaster

Sovereign -- Creatures you control have "Whenever this creature deals combat damage to a player, if that player has 4 or more cards in their hand, that player discards a card. Then, put a Gold artifact token onto the battlefield with "Sacrifice this token, add one mana of any color to your mana pool".
{t}: Exchange control of target artifact or enchantment you control with an artifact or enchantment an opponent controls