Skinny Doc is mistaken for one of the aliens that has landed on Earth and gets taken out into space in their ship. Meanwhile, one of those aliens is stranded on Earth and pretends to be Skinny Doc.
"Alien Again" contains the following tropes:
- Alien Among Us: The stranded alien decides to mimic the appearance of Skinny Doc and blends in so well with the other folks at the laboratory that nobody notices he's not actually Skinny.
- Alien Episode: Aliens visit Earth and accidentally get Skinny Doc caught up with them.
- Continuity Nod: The episode title being "Alien Again" is referencing how this isn't the only time the docs have been involved with extraterrestrials.
- Cranial Eruption: Skinny Doc develops a long bump on his head when he trips on one of the aliens' helmets. This is part of why he gets mistaken for one of them, as the bump looks like the antennae on the aliens' heads.
- Flying Saucer: Much like the previous alien-focused episode of Lamput, the aliens here ride around in this kind of spacecraft.
- Humanoid Aliens: The aliens look almost exactly like the Earth scientists that work at the lab, but with antennae protruding from their heads and only one eye.
- Mistaken for Aliens: One half of the episode's plot is that Skinny Doc is brought into a spaceship against his will due to his appearance being extremely similar to the aliens inside.
- Shout-Out: An issue of TIME Magazine featuring the docs' boss on the front cover can be briefly seen in the docs' bedroom.
