When I was little, I came up with a character based off one of my teddy bears named, simply, Teddy Bear. I used to play games with my brother(who I'm 100% sure isn't a furry currently). Teddy Bear was not on four legs, as we usually took our index and middle fingers and walked them around as a representation of him(for some reason). This character didn't develop into my fusona or anything. Actually, Teddy Bear was often interpreted as rude and evil, rarely ever nice (deep inside, I still loved him). Soon enough, my brother and I came up with the idea for there to be a planet filled with Teddy Bears, then becoming a sort of species. There are of course other things that made me a furry, like Jump Start Artist, a computer game for preschoolers where every character is anthropomorphic, but out of all, Teddy Bear would have to take the cake.
