Phlage, Titan of Fire's Fury

Lightning Helix has always been the cleanest expression of Boros efficiency: three damage, three life, one card. This is that spell handed a 6/6 body and a second life in the graveyard. The self-sacrifice clause is the pivot the whole design turns on. Cast it from hand for three mana and you get the Helix at a one-mana premium, the Giant sacrificing itself on entry before it can ever swing. That is a deliberately mediocre floor, and it exists to make the ceiling honest. Escape from the graveyard and the sacrifice trigger goes dormant: the Helix fires again on entry, once more on every attack, and the 6/6 stays behind to keep swinging. The five-card exile cost is the throttle. A single copy can only recur so many times before its own graveyard runs dry, which is what stops a resolved Phlage from grinding a game shut on its own. Note the timing seam this creates: because Phlage is a creature, the escape recast is locked to sorcery speed, so the recursion happens on your turn on your terms, never as an end-step ambush. Counter the escape cast and it never enters, so it deals nothing. But when it does resolve, the three damage lands immediately and again on the next attack. It collapses the old midrange sequence of remove, then threaten, then remove again into a single card that does all three jobs and comes back to do them once more.