"We suggest you don't spend a lot of time trying to figure out where this episode comes in in the timeline of the series — it doesn't. It's a storytelling aberration, if you'll allow."
For medical purposes, Smedley needs to know identify the species of every Muppet Theater employee. (It's a very specialized policy.) There's just one problem: Nobody's sure what Gonzo is.
Wait a minute! Didn't Muppets From Space establish that Gonzo is an alien? Well, it did, but come on — Who likes or cares about Muppets From Space? I'm actually really glad the Muppet people let Langridge do this... [...] And anyway, I hated the revelation that Gonzo was from another planet. So I'm totally in favor of applying some Wite-Out to that and saying Gonzo's heritage is still a mystery.
Daphne: Wow! I haven't seen—
Fred: Look away, Daphne. We all promised each other that we would never speak of him. Not ever!
Spike: Hey, aren't you supposed to be dead?
Rainbow Dash: This isn't canon.
Spike: There ya go! It's not canon!