Breath of Fury + Tervigon + Mass Hysteria

Breath of Fury

Tervigon

Mass Hysteria

How it works

1. Deal combat damage using the creature that has Breath of Fury attached and Tervigon, triggering Breath of Fury and Tervigon.
2. Resolve the Tervigon trigger, creating at least one creature token.
3. Resolve the Breath of Fury trigger, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to a creature token, then causing you to untap all creatures you control and to get an additional combat phase after this one.
4. Repeat each combat phase.

This brilliant loop centers on Tervigon dealing combat damage to a player, which not only generates a swarm of 1/1 green Tyranid creature tokens via its Spawn Termagants ability, but also triggers the attached Breath of Fury on that same creature. When Breath of Fury resolves, you sacrifice the creature it was on, move the Aura onto one of those newly minted tokens, untap all your creatures, and grant yourself an additional combat phase. Thanks to Mass Hysteria giving all your creatures haste, the newly targeted token can immediately attack in the next combat phase to repeat the cycle infinitely.