Mine is that at my age (barely made it into Gen Z on the old end) I just found out today that a Bo Weevil is an insect (beetle) and not some kind of mole or similar rodent.
My partner has Aphantasia. Brains are strange! She cannot visualize in her mind which makes it very challenging to do certain tasks and many things she does are based on muscle memory. Also interestingly when a song gets stuck in her head it is like she is making all of the sounds with her inner voice. For me, I can hear the song like there is a recording playing in my head.