Hm thats an interesting idea. It could be basically the same as nova, except you get x additional fire quanta, with x being the cost of the creature you sacrifice. Though admittedly that'd be a pretty weak card... It could maybe work with Phoenix's though since you'd get 8 total fire, and be able to revive it still for 1 fire (you'd need towers though to start. So no towerless fire rushes).