“It's all just a joke, repeating forever.”
—UserZero, Destroy the Godmodder 0rigins
Timeloops are a phenomenon in the Destroy the Godmodder series introduced by UserZero in the Destroy the Godmodder 0rigins cutscene Over Nine Thousand Trillion Years Older. In essence, the phenomenon dictates that at some indefinite point after the end of Destroy the Godmodder 2 (typically September 1st, 2015), the entirety of Fiction's timeline loops back to November 11th, 2011, the official release date of Minecraft, and will continue to do so for eternity.
UserZero is one of the only beings in Fiction to be aware of this phenomenon and to retain memories between loops - as such, she is aware that Fiction has looped in this manner over nine quadrillion times. She hasn't stated how these timeloops came to be, but has said it has something to do with the Zeroth Server's Yggdrasil. There are a few constants across every timeline - the Godmodder kills UserZero, the Godmodder achieves Omega+ Rank, and UserZero breaks out of Limbo to fight the Incarnate, piloted by an insane Godmodder on the verge of defeat. Everything else is completely variable across every timeloop, leading to an unholy amount of possible circumstances.
UserZero has theorized that Destroy the Godmodder 0rigins' timeline will be the final timeloop thanks to how badly Fiction's timeline has degraded, making the DTG canon the main series follows the penultimate timeline.