Fans Have A Theory About Penny's True Motives On Big Bang

Although "The Big Bang Theory" ran for 12 seasons on CBS), the character of Penny is still a mystery. Not much is known about her life before moving in across the hall from Leonard and Sheldon. In fact, the series never even revealed Penny's last name to viewers, (via Insider). However, that didn't matter much, because fans instantly fell for the lovable character. Despite Penny's bubbly personality and sweet demeanor, a wild fan theory paints the character in a much different light, per Screen Rant.

The theory, which originated on Reddit, claims that Penny may have been sent by foreign enemies to get close to Leonard, Sheldon, Raj, and Howard. The group of scientists have all worked closely with major groups such as the Air Force, FBI, and NASA, and Penny may have been used to spill their secrets and gather intel for other countries. 

Her lack of last name and interest in the geeky guys have raised flags among some viewers, who believe Penny was solely there to infiltrate their friend group. The theory also explains why Penny immediately begins to play dumb whenever scientific topics come up, even though she's proven on multiple occasions that she's smarter than she appears and listens intently when the men speak about their research. While the theory seems unlikely, some fans may now watch reruns of the show with fresh eyes.