Imaginary Pet

An oversized blue body at a price that should have broken something in 1998, sold with a self-destruct clause attached: empty your hand or the pet goes back to the office. That conditional is the whole bargain. The creature only stays put when you have nothing left to play, so the intended sequence runs against blue's instincts: dump everything, race while the body holds, and accept that a deck built to hoard counters and instants now wants to be empty by its own upkeep. The tension between "be enormous now" and "have nothing in hand later" is the entire design, and early aggressive blue builds that tried to exploit it leaned on a low curve to spend out before the bounce triggered. Watch what the timing does and does not buy you: because the return happens on your upkeep, the pet sits on the battlefield through the opponent's entire turn, fully exposed to their sorcery-speed removal and sweepers, unlike a creature that bounces at your own end step. The drawback is a liability on defense, not an evasion of it. The flavor and the mechanic describe the same idea, which is the cleanest thing about it: the pet exists only while you are not minding your hand, and vanishes the moment you have something better to hold.