Activate Altar of Dementia by sacrificing Michelangelo.
When Michelangelo dies, it and Deathrender trigger.
Resolve the Michelangelo trigger, returning it from your graveyard to your hand.
Resolve the Deathrender trigger, putting Michelangelo from your hand onto the battlefield and attaching Deathrender to it.
Resolve the Altar of Dementia ability.
Repeat.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite mill

Infinite self-mill

Michelangelo, On the Scene

Deathrender

Altar of Dementia

Activate Elvish Piper by paying {G} and tapping it, putting Michelangelo from your hand to the battlefield.
Activate Phyrexian Altar by sacrificing Michelangelo, adding {G}.
When Michelangelo dies, it and Elvish Piper trigger.
Resolve the Michelangelo trigger, returning it from your graveyard to your hand.
Resolve the Elvish Piper trigger, untapping it.
Repeat.

Elvish Piper

Phyrexian Altar

Thornbite Staff

Activate Sneak Attack by paying {R}, putting Michelangelo from your hand to the battlefield.
Activate Thermopod by sacrificing Michelangelo, adding {R}.
When Michelangelo dies, it triggers, returning it from your graveyard to your hand.
Repeat.

Sneak Attack

Thermopod

Activate Elvish Piper by paying {G} and tapping it, putting Michelangelo from your hand to the battlefield.
When Michelangelo enters, Intruder Alarm triggers, untapping all creatures.
Activate Phyrexian Altar by sacrificing Michelangelo, adding {G}.
When Michelangelo dies, it triggers, returning it from your graveyard to your hand.
Repeat.

Infinite mana creatures you control can produce

Infinite untap of all creatures

Intruder Alarm

Combos with "Michelangelo, On the Scene"