Totentanz, Swarm Piper

The death trigger runs on one deliberate restriction, and that restriction is the reason it never spirals: nontoken creatures only, so the Rats it produces cannot loop back into themselves the way a token-agnostic converter would. That single qualifier does all the balancing. It turns the card into a machine that spends your real, expendable bodies for a growing pile of attackers, which is the exact aristocrats math a Rakdos sacrifice deck already wants to run. Each Rat arrives with a built-in liability ("This token can't block"), a phrasing that scans as a downside but functions as direction: these are attackers, not a defensive wall, and the second ability spells that intent out. Paying to hand deathtouch to an attacking Rat converts a 1/1 with no evasion into a trade the defender cannot profitably take, so a swarm of individually irrelevant bodies becomes a threat the opponent must chump or eat. The Warlock Bard typing carries the flavor: a piper leading vermin, each fallen ally reincarnated as another rodent in the parade. The two halves solve separate problems. The trigger answers where the board comes from; the activation answers how the board gets through. Neither is much alone. Bolted together, they describe a deck that wants its creatures to die and then wants those deaths to attack.