Piru, the Volatile

A returning member of the original Elder Dragon cycle from the game's earliest days, redrawn under modern sensibilities and given a payoff that rewards letting go. The Mardu color identity is deliberate: white and black for the lifelink drain, red for the parting explosion. The upkeep tax is the fulcrum of the whole design. Paying each turn keeps a 7/7 flier with lifelink online, a rate that beats down and stabilizes at once, but the moment you can't or won't pay, Piru sacrifices itself and deals 7 damage to every nonlegendary creature. That death trigger is not a downside bolted onto a fragile body; it is the scheduled detonation the whole package plays toward. The sweep is asymmetrical (your own legends survive, most of your opponents' creatures do not), which recasts the sacrifice clause from a liability into an exit you control. The old problem of the fatty that dies for nothing gets solved cleanly here: kill Piru in combat or with removal and it still clears the field on the way out. It punishes the opponent who ignores it and the one who answers it alike, which makes the upkeep cost less a leash than a timer you can choose to let run out.