Here's the latest installment of the LeBron James Challenge ... courtesy of LeBron James!!

LBJ posted yet another shirtless workout vid Friday morning ... vibin' out to Meek Mill's new "Wins & Losses" album. This time, the King raps, sings and even maniacally laughs at his haters.

LeBron's been mocked by pretty much the entire Internet -- including Steph Curry -- for his first viral gym sesh, so it's only a matter of time before your timeline gets flooded with new challenge vids.

At one point, LBJ makes sure to point out one of Meek's lyrics directed at the President -- "Trump ain't feelin' us" ... which makes sense, considering Bron's never hidden his feelings towards POTUS.

As for LeBron's singing ... it's never too late for lessons, bro.

BANGIN' 'FIRST DAY OUT'