Termagant Swarm

The design puzzle here is turning a scaling creature into a resource that survives its own death. Ravenous sizes the body directly off the mana you sink in, so the counters aren't a bonus layered onto a fixed frame: they are the creature, which means power and the value on death are the same number. That's the wrinkle Death Frenzy exploits. Whatever this dies as, it hands back that many bodies, so a removal spell or a favorable block doesn't erase the investment: it converts it into a wide board of expendable tokens. The counters get sacrificed; the power does not.

That coupling makes it a self-fueling engine for the two directions Tyranid decks want to go at once. Go tall and it draws a card on the way in when the investment is large enough, rewarding the same big-X turn that makes the eventual death payout enormous. Go wide and the death trigger seeds a token swarm ready for the next sacrifice or the next attack. Sacrifice outlets change its axis entirely: instead of waiting for combat or removal, you cash the whole counter pile into a token army on your own timing, splitting one large creature into many small ones that dodge board wipes aimed at the big threat. It reads as a beater and plays as a battlefield you keep even after the beater is gone.