Klay Thompson took time out of celebrating his NBA championship victory to call out a Memphis Grizzlies player who gloated about a win over the Warriors earlier this year ... blastin' the dude as a "frickin' bum" and a "frickin' clown."
The target of Thompson's animosity was Jaren Jackson Jr., who tweeted a dig at the Warriors following a 123-95 win back in March.
"Strength in numbers," Jackson Jr. said, clearly mocking the Warriors' famous rallying cry after the victory.
Thompson revealed on Thursday night after beating the Celtics in Game 6 of the NBA Finals that the tweet REALLY pissed him off .