The theory about presidential candidate Hillary Clinton having a body double started trending on Twitter on Monday.

Users started using #HillarysBodyDouble after Clinton apparently was caught about to faint while going into her van after attending the 9/11 ceremony in New York on Sunday, Sept. 11, 2016. The ceremony marked the 15th anniversary since the terrorists attacks on Sept. 11, 2001. 

According to CBS News, Clinton "abruptly" left the ceremony around 9:30 a.m. after feeling "overheated."

“Secretary Clinton attended the September 11th Commemoration Ceremony for just an hour and thirty minutes this morning to pay her respects and greet some of the families of the fallen,” Clinton campaign spokesperson Nick Merrill said in a statement Sunday morning. “During the ceremony, she felt overheated so departed to go to her daughter’s apartment, and is feeling much better.”

Clinton headed to her daughter Chelsea Clinton's apartment and left there shortly after.

Clinton's doctor, Dr. Lisa Bardack, released a statement Sunday afternoon about the examination, saying Clinton was “recovering nicely” after becoming “overheated and dehydrated” earlier in the day. Bardack also noted that the candidate had been diagnosed with pneumonia Friday.

Conspiracy theorists started to say that Clinton actually has a body double to keep people believing that she has perfect health. The body double supposedly was used when Clinton existed her daughter's building with no agents around her., according to Inquisitr.

Most of the Twittersphere took the time to mock and tease the hashtag #HillarysBodyDouble. Here are the top memes:

There are plenty more memes and jokes on Twitter. Which one is your favorite? Sound off below!