Warren Oates (Reese Fowler) has difficulty maneuvering with his large mutant eyes. This is evident when he reaches for door knobs and edges of tables and chairs to sit down or lean.
According to the series' producer Joseph Stefano, "'The Mutant' was probably the worst show we did. Just terrible. I didn't care for the cast on it, either."
The alien creature that attacks Professor Lacosta is a reuse of one of the Zanti props from The Zanti Misfits (1963).
A box bearing the word "Daystar" is seen. This is a reference to the series' production company Daystar Productions.
Director Guillermo Del Toro was scared of this episode as a child. When he saw the mutant, he "started screaming and didn't stop."