After watching an episode of Jackanory, I was convinced one of my elder brothers was an alien. I used to watch him all the time for any tell-tale signs.....I'm still not sure after 30 years !
A childhood belief about family

others believed things like this
- Having seen enough red octagonal STOP signs in my time, I used to look out for green circular GO signs.— Gary
- I used to look for an Indian along the roadside because of signs that stated
"watch for fallen rock"— pam petry - I thought the ball-headed person in the Bic logo was an alien and communicated using alien-like noises.Anon
- Oh oh, I'm an alien, I'm a little alien...
Legal maybe?— Marina - i used to watch doctor who and every time i saw a darlic i wet myself literally.— Dan Barber
- When i was a kid, i thought that nematodes would eat our house like in one episode of SpongeBobAnon