Jegantha, the Wellspring + Horde of Notions + Altar of Dementia + Fires of Yavimaya

Jegantha, the Wellspring

Horde of Notions

Altar of Dementia

Fires of Yavimaya

How it works

1. Activate Jegantha by tapping it, adding that cannot be spent to pay generic mana costs.
2. Activate Altar of Dementia by sacrificing Jegantha.
3. Activate Horde of Notions by paying , causing you to cast Jegantha from your graveyard without paying its mana cost.
4. Repeat.

This infinite recursion loops Jegantha, the Wellspring straight from the graveyard back onto the battlefield, fueled by the exact five-color mana restriction its own tap ability provides. Because Horde of Notions lets you play Elementals directly from your graveyard for that exact color combination, and Fires of Yavimaya grants the necessary haste so Jegantha can tap the very moment it re-enters, the loop can immediately restart. Meanwhile, Altar of Dementia turns this endless cycle of returns and sacrifices into an infinitely repeating death trigger that mills out any target player completely.