The case
This is the case that made the Mandela Effect a household phrase. Stan and Jan Berenstain published the first Bear book, "The Big Honey Hunt," in 1962, and the family kept the shelves stocked through the '70s, '80s and '90s. The 1985 CBS cartoon put the name on the screen every Saturday.
Ask a room of people who grew up with the books how the name is spelled and most will say -stein. The books, the cartoon title cards and the authors' own names say -stain. There was never a spelling change, no reprint, no publisher switch. The A was always there.
Why our brains do this
Names ending in -stein are common and -stain is rare, so the brain files the unusual spelling under the familiar one. Hearing the name read aloud, where the vowel is ambiguous, does the rest.
Sources: Wikipedia — Berenstain Bears · Wikipedia — False memory: the Mandela effect
