Ichor Rats

Most infect creatures threaten poison only on connection, and the defending player decides whether that happens by blocking or trading. This one skips combat entirely. The entry trigger hands a poison counter to every player at once, the controller included, which makes it less a 2/1 threat than a clock that ticks regardless of the board. The symmetry is the whole design constraint: this is not a creature you race with, it is one you stack, and the body is almost incidental to the work the trigger does. Where it earns its slot is a deck that flickers or recurs the enters-the-battlefield clause, converting a fragile body into a repeatable poison engine that advances everyone toward ten counters at once, win condition by attrition rather than by combat damage.

That symmetry is also the honest cost. Looping the trigger ten times simply poisons the whole table, controller and opponents alike, so on its own the engine ends in a shared loss. The card only becomes one-sided when paired with something that breaks the symmetry: proliferate to push opponents over the line first, or an effect that prevents or removes your own poison counters. Outside that pairing it is a small creature with a self-inflicted drawback. But once poison is a resource you can manufacture from a trigger rather than deliver through an unblocked attacker, this is among the cheapest pieces that does it.