Whoa! Waittaminute! I’ve been arguing for years that it isn’t a drug song, it’s about growing up. But I always thought Puff was real (in context). He’s not a stuffed dragon that Jackie has imaginary adventures with. He’s a real dragon that Jackie goes to visit. (It’s a song! Of course that can happen. Why not)
Pooh and Eyeore et al were also real. I’m not sure about Hobbes.
A large number of dopers are wrong: