Cast an artifact in your hand by paying {0}.
Teshar triggers, returning Ambrosia Whiteheart from your graveyard to the battlefield.
When Ambrosia Whiteheart enters, it triggers, returning another artifact that can be cast for {0} from the battlefield to your hand.
Resolve the artifact spell cast in step 1.
Activate Ashnod's Altar by sacrificing Ambrosia Whiteheart
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite creature ETB

Infinite creature LTB

Infinite colorless mana

Infinite death triggers

Infinite creature sacrifice triggers

Infinite storm count

Artifact Castable for {0} that survives

Teshar, Ancestor's Apostle

Ashnod's Altar

Ambrosia Whiteheart

Activate any number of creatures you control by tapping them, adding at least {G}{W}{U}.
Cast Ambrosia by paying {1}{W}.
When Ambrosia enters the battlefield, it, Clement and Intruder Alarm trigger.
Resolve the Intruder Alarm trigger, untapping all creatures.
Holding priority, activate any number of creatures you control by tapping them, adding at least {G}{W}{U}.
Resolve the Clement trigger, returning nothing to your hand.
Resolve the Ambrosia trigger, returning Clement from the battlefield to your hand.
Cast Clement by paying {1}{G}{U}.
When Clement enters the battlefield, it and Intruder Alarm trigger.
Resolve the Clement trigger, returning Ambrosia from the battlefield to your hand.
Resolve the Intruder Alarm trigger, untapping all creatures.
Repeat.

Infinite mana creatures you control can produce

Infinite untap of creatures

Clement, the Worrywort

Intruder Alarm

Cast Nethroi either from your hand or from the command zone for its mutate cost by paying {4}{G/W}{B}{B}, putting it under a non-Human creature you control.
Nethroi triggers, returning Ambrosia Whiteheart and Mitotic Slime from your graveyard to the battlefield.
When Ambrosia Whiteheart enters, it triggers, returning Nethroi from the battlefield to your hand.
Activate Phyrexian Altar twice by sacrificing Ambrosia Whiteheart and Mitotic Slime, adding {B}{B}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {1}{G/W}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {3}.
Repeat.

Combos with "Ambrosia Whiteheart"