This is one of the rare Calvin And Hobbes strips that is very much a product of it’s time. Usually Watterson’s writing is timeless and universal. But by specifically mentioning the year in the strip he places the gag within a dated context.
What makes Lio different, though, is it’s not his imagination. The things in Lio’s world are really happening.
Unlike, say, Calvin And Hobbes, where Calvin’s imagination WAS his world, and therefor he was able to control it. Reading Lio one gets the sense that the darkness in Lio’s world is so dark BECAUSE he’s not in control of it. Everything he experiences is really happening.
Show me a BC that is actually poignant and funny, and I’ll show you a BC from about 40 years ago.