The Mandela Effect

Collective false memories
Similar false memories are sometimes shared by multiple people. For example, a somewhat commonly reported false memory is that the name of the Berenstain Bears was once spelled Berenstein. Another reported example are false memories of a movie starring the comedian Sinbad, called Shazaam. In one study, 92% of those familiar with a train-station clock that had been stopped 16 years after a terrorist attack as a symbolic commemoration, falsely remembered that it had been stopped since the attack itself. In 2015 this phenomenon was dubbed the "Mandela Effect" by self-described "paranormal consultant" Fiona Broome, in reference to a false memory she reports, of the death of Nelson Mandela in the 1980s (rather than in 2013), which she claims is shared by "perhaps thousands" of other people. Broome has speculated about alternate realities as an explanation, but most commentators suggest that these are instead examples of false memories shaped by similar factors affecting multiple people, such as social reinforcement of incorrect memories, or false news reports and misleading photographs influencing the formation of memories based on them.