Citations:Oncest

Proper ship: "(fandom slang) the selfcest ship of the Onceler from the Lorax and his alter ego the Greedler or a fan-created variant"

 * 2012, Aja Romano, "Self-cest: 5 characters who get paired with themselves", The Daily Dot, 22 October 2012:
 * Fortunately for fans, in the film, the Once-ler transforms over time into an alter-ego known as the Greed-ler. In the fandom, the Once-ler doesn’t just become the Greed-ler; he turns into several different variations on an ever-changing persona. He can be any kind of character you want him to be.
 * The Once-ler fandom calls this ship Oncest. We’re not sure how it works; we just know that it’s incredibly popular (link NSFW).
 * 2018, Petrana Radulovic, "Is The Grinch the new Once-ler, Tumblr’s autosexual Lorax idol?", Polygon, 12 November 2018:
 * The Once-ler fandom was so loud and spread across Tumblr that, even if you had no idea what the hell Once-ler was from, your dashboard was plastered with people reblogging and posting Oncest that you eventually found out one way or another.
 * 2021, Palmer Haasch, "'Loki' reignited the internet's debate about 'selfcest,' or falling in love with a version of yourself, with its main relationship", Insider, 16 July 2021:
 * The Onceler, the main character from "The Lorax" animated film, sparked a passionate fandom on Tumblr that eventually led to fans shipping him with fictional variations of himself in a phenomenon called "Oncest."