Magister Sphinx

The trick is the word "becomes," which makes this a setter rather than a healer or a burn spell: the life total is overwritten to a fixed 10, not adjusted from where it stood. Against an opponent sitting above that mark, the entry trigger erases everything between their current number and ten in one stroke, and because it sets rather than damages, it slips past damage prevention and redirection; you are not chipping at the number, you are replacing it. The mandatory targeting is not a trap, because the choice of target is yours: aimed at an opponent above ten it is a brutal swing, aimed at yourself when an aggressive board has dragged you low it is a reset that buys room. The real cost lives elsewhere. The trigger overwrites once, on entry, so the 5/5 flier still has to do the closing work afterward on its own clock; it does not snap a life total down and then connect in the same turn. But "fires once" understates the design, because an entry trigger is among the most reusable effects in the game: flicker it, bounce it, recur it, and you can drop the same opponent back to ten again and again. As a targeted ability it answers cleanly to protection from artifacts, white, blue, or black, which is the tidiest out. A card built to make the arithmetic suddenly simple, and to punish anyone who treated a healthy life total as a safe one.