I used to believe that Wombles (from the show 'Wombles of Wimbledon Common' - all you Brits should be familiar!) were real.
Now, I was a smart kid; I didn't think that Wombles really went around in clothes and talked and so on. But I thought that they were real creatures on which the show had been based.
We lived in Wimbledon at the time, and my mum would often take me to the Common to look for 'Wombles'. She was of course just playing along with the belief that real Wombles in clothes and hats were cleaning up the park. However, I was deadly serious about finding a 'real' Womble, which I imagined was a small scurrying mammal.
My mum was very amused when, at 18, I was talking about how we'd never seen an actual Womble at the Common in all those years. I was actually pretty saddened to learn there was no such thing.
A childhood belief about tv

others believed things like this
- "The wombles of Wimbledon Common are we" meant that there were loads of them...— Mike
- I used to believe there were loads of Wombles, until about a minute ago...— Nat
- i used to believe dragon ball z was real
and namek was in another dimension
and every show on tv was realAnon - I used to beleive that the computer bugs were real creatures that lived in your pc and ate away at it.— BoBo
- I used to believe the T.V show "War of the Worlds" was for real, that those aliens were REALLY coming for us. — Adelaida
- It was common "knowledge" where I lived that if you picked dandelions then you would wet the bed.— Holly