Infected Vermin

A repeatable Pestilence stapled to a fragile 1/1 body, with the same fatal catch that has always defined symmetrical damage engines: it hits its own controller, and it hits the rat. For per pull the body pings everything for one, so the engine immolates itself on the very first activation unless something props it up. The Threshold mode raises the ceiling to three damage each, the number that clears most early creatures and pressures life totals in earnest, but it asks for a stocked graveyard, which in practice means committing to a mill-heavy or expendable-creature shell that can afford to feed the yard while still standing under its own fire. That double demand (survive the damage, and bank seven cards to make the damage worth banking) is what keeps the card honest and also what keeps it marginal: the decks that can fill a graveyard quickly are rarely the decks that want to sit behind a self-destructing pinger burning the board down a point at a time. It belongs to an early-era argument about whether the cards in your bin are something you spend or something you simply watch accumulate, and this rat lands on the cautious side: real reach, but only for a deck patient enough to pay both halves of its tax and absorb the symmetrical burn while doing so.