Infinite Reflection attached to Cultivator Colossus.
Steps
Play any land from your hand.
The land enters the battlefield as a copy of Cultivator Colossus due to Nature's Revolt and Infinite Reflection.
When the land enters the battlefield, it triggers.
Holding priority, activate Altar of Dementia by sacrificing the land.
When the land dies, Enduring Renewal triggers, returning the land to your hand from your graveyard.
Resolve the Altar of Dementia ability, causing target player to mill cards equal to the land's power.
Resolve the land's trigger from step 3, causing you to put the land onto the battlefield from your hand, draw a card, and then decline to put another land onto the battlefield.