At the end of the turn, my opponent gets his creature back. At this time, what happens to the Dead Iron Sledge or any other equipment I attached to said creature? Who controls the equipment after the creature is returned?
My argument is that if the exchange were the other way, the equipment would remain under control of the one who cast it, but the equipment would be attached to the stolen creature. This is clear in Wizards rulings.
Thus, when the creature is returned, it will keep the Dead Iron Sledge attached to the opponents creature.