Mikaeus, the Unhallowed + Defiant Greatmaw + Thermopod

Mikaeus, the Unhallowed

Defiant Greatmaw

Thermopod

How it works

1. Activate Thermopod's second ability by sacrificing Defiant Greatmaw, adding .
2. When Defiant Greatmaw dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
3. When Defiant Greatmaw enters the battlefield, its first ability triggers, putting two -1/-1 counters on it.
4. Defiant Greatmaw's second ability triggers, removing a -1/-1 counter from another creature you control.
5. Repeat.

This clever loop turns Mikaeus, the Unhallowed into an engine for infinite red mana and endless triggers by leveraging his ability to grant undying to non-Human creatures. When you sacrifice Defiant Greatmaw to Thermopod, it generates the red mana you need while sending the Greatmaw to the graveyard, only for its undying ability to bring it right back with a +1/+1 counter. That return immediately triggers Defiant Greatmaw's own entrance ability to place two -1/-1 counters on itself, which neatly annihilates its existing +1/+1 counter through state-based actions while also letting you clean off any accumulated -1/-1 counters from other creatures using its second ability. Because the +1/+1 counter is removed this way, Defiant Greatmaw is left completely clear to die and resurrect all over again.