Bill Cosby is no stranger to criticizing other comedians, but in the 1970s, he allegedly found himself on the receiving end of a little criticism of his own. Who would’ve had the nerve to go after Cosby at that stage in his career, you ask? Well, as it turns out, Tom Smothers, one-half of the popular Smothers Brothers comedy team, was one of Cosby’s most vocal detractors in those days. By most accounts, the two didn’t care for one another at all, and had what was described as a “running disagreement” from the moment they first met.

Smothers appears to have been the instigator of the feud, which he said stemmed from the fact that Cosby didn’t have anything to say about the Vietnam War and wasn’t as vocal as Smothers felt he should have been during the Civil Rights Movement. Cosby apparently wasn’t pleased with Smothers chiding him publicly, and would greet him coldly whenever the two would cross paths. Things got even more tense while Cosby and Smothers were attending a party at the Playboy Mansion in October 1976. Without knowing that Cosby’s short-lived sketch comedy series, Cos, had just been canceled, Smothers told Cosby, “I liked your show, it was a really good effort.”

Cosby allegedly interpreted this as a dig and responded by saying, “Maybe sometime I’ll knock you upside the head one of these days.” Smothers dared him to “go ahead and try” and walked away without thinking much of it. A couple of months later, Cosby made good on his promise and (allegedly!) sucker-punched Smothers from behind at another one of Hugh Hefner’s parties, knocking him to the ground. Cosby then stood over him, screaming, “I’ll kick your ass,” after which Hefner reportedly stepped in to separate the pair.

Cosby and Smothers never saw each other again, and their feud wasn’t resolved as of Smothers’s death in 2023. In an interview from 2006, Smothers complimented Cosby’s comedy, but said that he still thought his fellow comedian was “an asshole.” He also joked about getting Cosby back with a retaliatory sucker punch if Cosby ever turned around in front of him. “It probably won’t hurt,” Smothers quipped, “We’ll be hobbling around in our walkers.”