Eyeblight Assassin

The -1/-1 stapled to the body is the entire transaction, and its bounds are tight: the debuff evaporates at end of turn, which makes this a tempo and combat tool rather than durable removal. Point it at a one-toughness creature and it reads as a kill spell attached to a 2/2; point it at anything bigger and it shrinks a blocker, sneaks an attacker through, or bends one round of combat math your way. The Elf Assassin line is the quiet upside that earns it a slot beyond raw rate, feeding both the tribal payoffs that reward Elves and the death-and-removal angle that rewards Assassins, so it carries relevance in two lineages at once. What holds it back is the timing window. The effect fires on entry, at sorcery speed in practice, so you cannot stash it as a combat trick or an instant-speed answer the way Disfigure or Tragic Slip can be sprung on a blocking or attacking creature. The one-turn nudge comes along for the ride, valuable exactly when a single point of toughness decides a trade, and forgettable when it does not.