SAN FRANCISCO — Susman Godfrey on Wednesday filed suit against Apple Inc. on behalf of a Japanese company that says the tech giant ripped off the trademark for “Animoji” when it announced a feature for the moving graphics at last month’s iPhone X launch.

Emonster k.k., owned by a U.S. citizen living in Japan named Enrique Bonansea, alleges that Bonansea came up with the term “ANIMOJI” in 2014 and registered it at the U.S. Patent & Trademark Office the following year. He’s been using the name to market an app for moving emojis in Apple’s own app store since 2014, according to the complaint.