When I first heard of the movie "Close Encounters of the Third Kind" I thought that the Third Kind was the name of the alien race on it. I figured humans were the First Kind but wasn't sure who the Second Kind would be..
A childhood belief about aliens

others believed things like this
- I used to wonder what kind of insect "uncles" were named after.
I had "Ants" figured out.— Kimberly in AZ - When my dad was little he thought that mistletoe was some kind of aircraft.— xoxo
- I thought Marco Polo was a kind of shirt.Anon
- When I was little I thought that a "wallflower" was a kind of flower that grew on walls.— A. Nonny-Muss
- The buckinghams song "kind of a drag", i always thought they were singing, "Canada Dry"— bobbybobby
- I thought that "heck" was a less horrible version of hell for people who were only KIND OF evil.— Oizys