Science fiction cartoon
Cartoon of alien science fiction fans
Aliens at a science fiction convention
One of the extraterrestrials in the cartoon is wearing a sci-fi tee shirt with the face of an alien on it.
The joke is that here on earth scifi fans would be wearing T-shirts with pictures of “greys” on them (Greys – grey hairless creatures with big eyes – being the standard contemporary image of an alien, a successor to the ‘little green men’ of the mid to late 20th century). On the aliens’ planet the tee shirt has a picture of a human on it, because to the aliens humans are the aliens