Memories aren't always accurate reflections of reality. From childhood friendships to recent domestic squabbles, your mind tends to embellish—if not outright fictionalize—your experiences. But what does it mean when your inaccurate recollections are about something from the broader culture and not your personal life? And what if thousands of strangers share the same false memory? If you can relate to this, you've experienced the Mandela effect.

Blogger Fiona Broome coined the phrase “Mandela effect” in 2009. While attending a conference, she discussed the tragic passing of Nelson Mandela in the 1980s. Many people she spoke to also recalled the South African president dying in prison, and some even remembered watching news coverage of the event on TV. But Mandela was very much alive at the time of the conference, and when he died four years later in 2013, he was a free man.

According to Broome, the Mandela effect is defined as a false memory shared by multiple people. Though it seems like a freak occurrence, instances of the phenomenon are fairly widespread. Do you remember the Berenstein Bears from your childhood? How about the movie Shazam starring Sinbad as a genie? Or the iconic Star Wars (1977) line “Luke, I am your father?”

All of the above are examples of the Mandela effect. In other words—none of it happened. The Berenstein Bears were really the Berenstain Bears; the genie movie you're thinking of is Kazaam (1996) starring Shaquille O'Neal, and Darth Vader actually says “No, I am your father.” Even after learning the truth, many people will continue to swear by their false memories. Some are so confident in their recollections that they cite the Mandela effect as evidence of alternate realities. So what's really behind the phenomenon?

Psychologists blame the Mandela effect on the way our brains record and retrieve information. Memories aren't perfect snapshots of moments as they occurred in real life. When we recall something, we may only have access to part of the true story, so our brains pull relevant information from different memories to fill in the gaps. That's why so many people remember a live-action comedy about a genie from the 1990s, but not the exact title or star.

If the above examples of the Mandela effect don't apply to you, you may still be shocked to hear that the Monopoly man never had a monocle, and Tom Cruise doesn't dance in Ray-Bans and his underwear in Risky Business (1983). Here are more examples of the phenomenon.