Infinite creature ETBInfinite creature LTBInfinite combat phasesInfinite creature tokens with hasteInfinite death triggersInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of creatures you control
How it works
Declare Grub and Combat Celebrant as attackers, choosing to exert Combat Celebrant as it attacks. Grub and Combat Celebrant trigger.
Resolve the Grub trigger, putting a -1/-1 counter on Combat Celebrant and then creating a tapped and attacking token copy of it.
Combat Celebrant dies as a state-based action due to having 0 toughness.
Resolve the Combat Celebrant trigger, causing you to untap all other creatures you control and causing you to get an additional combat phase after this one.
Repeat each combat phase, using the Combat Celebrant token instead.
This clever loop transforms Combat Celebrant's aggressive potential into an infinite swarm of additional combat phases. By pairing them with Grub, Storied Matriarch // Grub, Notorious Auntie, every attack lets you place a -1/-1 counter on Combat Celebrant to create a temporary, attacking token copy of it, gracefully bypassing the legend rule and sacrificing the original to trigger death effects while the token carries the torch. Meanwhile, having Anger in your graveyard ensures that your newly created token copies immediately enter the battlefield with haste, ready to swing right away and keep the extra combat steps rolling endlessly.