Elmo, a cheerful red Muppet, has more than 650,000 followers on X. "Elmo's X account was briefly compromised by an unknown hacker who posted disgusting messages, including antisemitic and racist posts," Sesame Workshop said in a statement, adding the account has since been secured.

"Elmo's X account was briefly compromised yesterday by an unknown hacker who posted disgusting messages, including antisemitic and racist posts. The account has since been secured," a spokesperson for Sesame Workshop, the nonprofit educational organization behind Sesame Street, said in a statement to ABC News on Monday.