You control a nontoken artifact creature that can be cast using ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol)
Steps
Activate
Ashnod's Altar by sacrificing the nontoken artifact creature, adding ({C} magic symbol) ({C} magic symbol)
The creature dies, triggering
Enduring Renewal, returning the creature from your graveyard to your hand
Imotekh's first ability triggers, creating two 2/2 Necron Warrior artifact creature tokens
If necessary, activate
Ashnod's Altar by sacrificing one or both Necron Warrior tokens, adding ({C} magic symbol) ({C} magic symbol) for each token sacrificed
Cast the artifact creature by paying its mana cost
Repeat
Results
Infinite creature tokens
Infinite colorless mana
Infinite ETB
Infinite LTB
Infinite death triggers
Infinite sacrifice triggers
Infinite storm count
Infinite blinking of artifact creatures you control