COLTON CUMBIE – the most hated SURVIVOR contestant ever – is back on the CBS reality show, but he’s promised to clean up his act, sources say.

His outrageous antics on “Survivor: One World” in 2012 led to the hunky gay bad boy being blasted as racist, elitist and a bully.

Colton’s mother even received death threats over his smack talking. But he still decided to compete on this season’s “Survivor: Blood vs. Water,” where he’ll be squaring off against his fiancé, Caleb Bankston.

“My mom got e-mails saying, ‘You should kill yourself for having a child that way,’ ” Colton reportedly said.

A source close to the 22-year-old student teacher from Alabama added: “When Colton’s mother told him about the threats, he was in tears.

“He publicly apologized for his behavior, and the threats slowed down. But they never stopped completely.

“So when his family and friends learned he was returning to the show, they literally begged Colton not to go for fear the ugliness would start up again.”

Colton dubbed himself “the evil queen” during his first shot on “Survivor.” And complaints flooded CBS and the “Survivor” website after he called his African- American tribe mate Bill Posley “ghetto trash” and referred to Leif Manson, a little person, as a “Munchkin” and “Oompa Loompa.”

His unpopular run ended when he was forced to leave early due to a bacterial infection.

“This time around, Colton has promised to prove he’s not a hateful person,” said the insider. “Colton wants to make his mother proud this time.”