Mairsil, the Pretender

A single, audacious idea sits under this 4/4: instead of caring about what a permanent does on the battlefield, it strips the activated abilities off artifact and creature cards entirely and grafts them onto one body. Each cage counter is a permission slip, and the abilities don't fire from exile: the card gains them, and you activate them from the battlefield as if they were printed on this Wizard itself. The deckbuilding exercise becomes assembling a toolbox of abilities worth caging rather than worth casting normally, because the cages sidestep whatever it would cost to get those cards into play. The "once each turn" clause is both the cost of admission and the engine's governor: it stops any single ability from looping infinitely while still letting you chain a dozen unrelated effects in one sequence. The crucial restriction is in the wording. Only activated abilities carry over, the ones written as a cost followed by an effect. Static abilities stay behind, as do triggered abilities, so an enters-the-battlefield trigger does nothing once its card is caged; some keywords translate and some do not, depending on whether the keyword resolves to a cost-and-effect line or a static or triggered rule. That narrows the search to true cost-then-effect abilities and rewards the player who hunts for one whose cost is cheap enough, or whose payoff is broken enough, to bend the once-per-turn rule into something resembling a combo. The body is almost incidental; the deck is the bank of abilities you spend a game wiring together.