Mockingbird

Clone effects have almost always priced the copy at a fixed rate: pay four or five mana, become whatever you point at. This one folds the copy target into the X you pay, so casting cost and copy ceiling become the same number. Spend two mana and you get a two-drop; spend six and you can copy a six-drop off the battlefield. That coupling is the whole engine of the design, because it turns a Clone into a scaling curve-topper that never overpays for a small body and never falls short of a big one. The cost only cares about mana value, not board state, so a cheap copy of an expensive creature is off the table by construction: to become a five-drop you have paid five. The floor is worth noting too. Fixed-cost imitations rot in hand when the board offers nothing worth copying; here you can decline the copy entirely and cast a flying 1/1, so there is always a play. And the copies it makes are strictly upgraded: everything it becomes gains flying and a Bird type, which quietly matters for evasion and for any deck counting Bird bodies. A shapeshifter that is also always at least a functional evasive one-drop is a more honest floor than the archetype usually offers.