Lizzo Wears 'South Park'-Themed Ozempic Alternative Costume

Lizzo's going down to "South Park" to have herself a time ... dressing up as the Ozempic alternative named after her for Halloween -- months after cracking up over the viral episode.

The singer-songwriter posted photos of her Halloween costume this year ... a box of "Lizzo" from the hit adult animated show -- with a measuring tape cinched around her waist like a belt.

Waiting for your permission to load the Instagram Media.

She added advertising slogans to the background ... saying Lizzo is a great way to lose guilt and gain confidence.

Remember, when "South Park: The End of Obestiy" dropped in May, fans were blown away by the jokes made about Lizzo -- where basically characters in the show said they didn't care about their weight, like Lizzo, instead of taking drugs.

Lizzo reacted to the scene on social media ... taking the joke in stride and seemingly laughing it off -- so, no harm, no foul.

That said, Lizzo recently showed off her own weight loss in a wild reveal video ... and, she's been hitting the gym hard in the months since the show came out.

She says she looks great either way -- before or after the weight loss -- so, she's probably saying people don't need to take any Lizzo if they don't wanna!

We've reached out to "South Park" creators Trey Parker and Matt Stone about Lizzo's costume ... so far, no word back.