Skinrender

Three -1/-1 counters is the number that does all the work. It kills any creature with toughness three or less outright, and against bigger bodies it shrinks them permanently rather than tapping them down or pushing them back to hand. Permanence is what black is buying by stapling removal to a body: Doom Blade trades one card for one creature and leaves nothing behind, while this leaves a 3/3 on the table after the trade resolves. The counters are also a quieter kind of removal than destruction. They dodge indestructible, they ignore regeneration shields, and they cap a creature's growth, which matters against anything that wants to grow from a small base. The trade-off is the trigger: the counters land only when the creature enters, at sorcery speed, with no way to hold them for a combat surprise. You commit on your own turn, on a target already on the board, and you accept that the answer arrives a beat slow in exchange for a permanent body and a permanent effect on whatever survives. That permanence cuts the other way too, and the catch is worth naming: the counters live on the targeted creature, not in some abstract ledger, so a creature bounced to hand and recast returns as a fresh object with full toughness and no marks on it. The shrink sticks only as long as the creature does.