Quagmire Lamprey

The threat here is the offer, not the body. Block it and you watch a creature shrink: a -1/-1 counter lands on whatever stands in the way, so the blocker that was meant to trade up instead trades down (and a 1/1 blocker simply dies on the spot before damage). The design quietly inverts the normal combat math. Most evasion makes a creature harder to stop; this one punishes the act of stopping it, which means a small body on defense can never profitably eat the attack. Stack the trigger turn after turn and a single 1/1 grinds through a board the way a deterrent fence works: nothing forces the opponent to block, but blocking always costs more than letting the point of damage through. The counter is what tethers the rate. There is no removal stapled on, no instant-speed flexibility, just a combat tax that only fires when the opponent chooses to engage, and only on the creature that engaged. It rewards patience over tempo, which is why a 1/1 with this much grind in it asks to be built around rather than jammed.