- Attack of the 50-Foot Whatever: Gulpo becomes absolutely massive in the climax of the episode, being tall enough to barely fit inside of Professor's lab.
- Clipped-Wing Angel: Felix manages to defeat him by dousing him in the same shrinking formula Poindexter used on Felix in the first place, returning Gulpo back to his microscopic size.
- I'm a Humanitarian: Gulpo tries to eat Felix alive when he first encounters him, but Felix socks him in the stomach and runs away.
- Last-Second Word Swap: We get this gem when Poindexter asks his uncle the Professor where he's going for the evening...Professor: To the wrestling-(clears throat) I mean to the opera! Harrumph!
- Lone Wolf Boss: Gulpo isn't associated with Professor or any other Felix villain; he's just a ravenous amoeba who ends up becoming a threat to Felix thanks to Poindexter.
- One-Winged Angel: Poindexter unwittingly makes Gulpo big enough to barely fit in Professor's lab by accidentally sprinkling him with the same growth formula that he used to restore Felix back to normal.
- Talk to the Fist: Felix socks Gulpo with a brutal punch to the stomach when Gulpo tries to eat him alive.
- Villain of the Week: Gulpo is a oneshot villain who only appears in this episode (although he would make a reappearance decades later in the NES video game).