Merfolk Thaumaturgist

The tap ability rewrites a creature's stat line by editing the two numbers it lives by, and the math only kills in one direction: a creature with 0 power becomes a 0-toughness body that dies to state-based actions the instant the switch resolves. Everything else trades survival for offense or offense for survival. Point it at your own 5/1 glass cannon and it becomes a 1/5 that lives through the swing it was built to die in; point it at a defensive 0/4 and you have erased the blocker entirely, since a 4/0 cannot stay on the battlefield. The asymmetry is the engine: power and toughness are different resources, and a creature tuned around one is exposed in the other. A symmetrical 4/4 is immune, because there is nothing to invert. What it does best is bend combat math against lopsided creatures: shrinking a fragile high-power attacker into a survivor, or collapsing a wall whose entire value is toughness. The 1/2 frame is incidental; the value is the activation plus a board full of skewed targets to exploit. Where certain one-shot instants perform the swap once, this Wizard repeats it every turn for nothing more than a tap, which is what separates a trick from an engine. The cost is finding reliable lopsided targets, and that scarcity is the only thing keeping the activation honest.