Attorneys for Elon Musk are asking a U.S. District judge to throw out a defamation lawsuit filed against the Tesla chief executive on the grounds that Musk’s “pedo guy” tweet about a British cave diver amounted to little more than a schoolyard spat that is still protected free speech.

Musk’s lawyer’s filed a motion in U.S. District Court in Los Angeles on Wednesday to dismiss the suit brought by cave diving expert Vern Unsworth on the grounds that Musk was defending himself following negative statements that Unsworth made about Musk in a TV interview. The issues between the two stemmed from Musk offering to send a mini-submarine to Thailand to aid in the rescue of a boys soccer team, and their coach, who had been trapped in an underwater cave.

Unsworth made light of Musk’s offer of assistance, which led to Musk soon calling Unsworth “pedo guy” in a tweet, alleging Unsworth had an underage child bride, and finally daring Unsworth to sue him over his statements. Musk soon went back on Twitter and apologized for his remarks.

But, that wasn’t enough for Unsworth, who in September filed libel and slander charges seeking at least $75,000 in compensation from Musk.

In their motion Wednesday, Musk’s lawyers said their client’s statements, while being over the top, were such that no one should have taken Musk seriously, and also protected free speech under the First Amendment to the U.S. Constitution.

The lawyers argue that Musk was legitimately defending himself following Unsworth’s negative comments about Musk’s offer to help with rescue the Thai soccer players.

A hearing about Unsworth’s lawsuit against Musk is currently scheduled for April 1, 2019.