When I was a kid, I was jealous of my sister, because she had imaginary friends, and I didn’t. Because Rokko, the three-inch tall invisible deer who followed me around in a little airplane, was real. Then again, being jealous of my sister was rather a habit I had growing up, so take that for what it’s worth. I do definitely remember when I first met Rokko, and that stemmed from jealousy: We were walking in Grampap’s woods, and everyone else kept saying that they were seeing deer, but I didn’t see any. So towards the end of the walk, I managed to find a little patch of light and shadows that I could convince myself was in the shape of a deer, and that was Rokko. Many years later, my mom told me that probably everyone was teasing me in the first place, and nobody saw any deer.
I also had an imaginary superhero named Superfeet (it’s a long story), but I never really met him, and a little later I met some imaginary aliens. Actually two sets of imaginary aliens; there were good guys and bad guys. I certainly talked about the aliens as though they were real, and I knew all sorts of details about them, but I’m not sure how “real” I really thought they were.