Bloodflow Connoisseur

A sacrifice outlet with the payoff folded into the same card, which is the design idea worth dwelling on. Most outlets hand the value off to a partner: Blood Artist supplies the drain, an altar turns bodies into mana, Phyrexian Altar pays you in colored mana for the next play. This one keeps the reward to itself, banking each sacrifice as a permanent +1/+1 counter rather than asking another card to convert the dying creature. That self-contained engine is also the catch: the counters all live on a body that started as small as bodies get, so a single removal spell erases every creature you fed it. No drain, no card, no mana survives once it dies; the fragility is the price for an outlet that costs no mana to activate. And mana-free is the operative word, because the activation has no per-turn limit either. On a board built to die on purpose (token swarms, recursive threats, anything you would rather sacrifice than chump-block with), it can pour an entire battlefield into one lethal attacker across a single main phase. It is a build-around that brings the converter but not the engine: you have to supply the stream of expendable creatures, and you have to protect the thing carrying all your investment, because everything you spent is sitting on a 1/1 with a target on it.