Homestuck

A group of teens unwittingly bring about the end of the world by installing the beta version of an upcoming computer game, Sburb. The teens soon come into contact with a group of Internet trolls who are revealed to be horned aliens, and these trolls work with the kids to create a new universe by completing the game.

Homestuck is a webcomic that started in 2009. In 2012, its creator posted and surpassed funding on a Kickstarter to make a game based on it.