More smack talk in the war between two former "Biggest Loser" co-stars -- this time Jillian Michaels is firing back at Cara Castronuova with some good ol' fashioned venom-laced sarcasm.
We broke the story ... Cara -- who was a trainer on the show -- ripped Jillian apart over Michaels' poor showing at the Malibu triathlon earlier this month, calling her an embarrassment.
This weekend, Michaels returned to Malibu -- where she offered up some brand new excuses for her abysmal showing (bad wet suit, bike problems, a horse?) and vowed to do better in the race next year.
Then, it was open season on Cara.
Check out the clip -- we're guessing these two ain't opening a gym together anytime soon.