Philadelphia, Pennsylvania - President Joe Biden joined in the mocking of Donald Trump, whose bizarre never-ending dance party at a rally left both supporters and detractors confused.

"He stood on the stage for 30 minutes and danced," Biden said at an event in Philadelphia.

"I'm serious. What's wrong with this guy," Biden asked, calling Trump a "loser."

Trump cut a campaign town hall in Pennsylvania short on Monday after it was interrupted by two medical emergencies due to the extreme heat. The Republican candidate did not leave the stage immediately, but asked for Ave Maria to be played.

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The former president then requested a range of other songs, to which he lazily swayed. "Let's just listen to music," he said, cancelling the planned Q&A session. "Who the hell wants to hear questions, right?"

Nine songs were played in total, ranging from opera to Guns N' Roses and Elvis, with Trump occasionally alternating his dance moves while standing in place alongside an awkwardly bopping South Dakota Governor Kristi Noem, staring into the crowd

Democratic presidential candidate Kamala Harris also mocked the episode.

The VP shared a montage of clips showing Trump bobbing to different songs, commenting sarcastically: "Hopefully he's okay."

Trump campaign spokesperson Steven Cheung, meanwhile, described it as a "total lovefest."