Everflame Eidolon

Bestow's whole pitch was that an Aura never had to feel dead in your hand, and this is the firebreathing version of that promise. Cast it cheap as a 1/1 body when the board is empty; pay the bestow cost when you have a creature worth pumping, and the pump ability follows the card wherever it lives. That last clause is the clever part: the activated ability reads itself differently depending on its current state, granting +1/+0 to the creature when it's a body and to the enchanted creature when it's an Aura, so the same mana sink works on either side of the bestow flip. The +1/+1 static buff stacks on top, turning a host into a repeatable threat that survives the host's death by simply becoming a creature again. The design tension is that the firebreathing is the reason to keep paying mana, and bestow is the reason the investment doesn't evaporate to a single removal spell: kill the host, and you're left holding a 1/1 that can still mash the pump button. It's a modest rate, but the dual-mode pump and the death-insurance built into bestow give it more staying power than its stat line suggests, which is exactly what the mechanic was built to deliver.