Buffyverse Wiki
Buffyverse Wiki

Gill Monster[1] was a race of supernatural creatures who had mutated from humans into fish hybrids. These monsters were the result of steroids Coach Carl Marin administered to the Sunnydale High swim team in 1998.[2]


Marin managed to find the solution to old Soviet Experiments on the DNA of fish, such as tarpon and mako shark, to improve the performance of Olympic swimmers. Even though the formula was successful on the swim team of Sunnydale High School, extended use eventually led to the boys transforming into humanoid fish-like monsters. Four students underwent the transformation: Dodd McAlvy, Cameron Walker, Gage Petronzi, and Sean Dwyer.[2]

When transforming, the person's skin would completely shed off, leaving what appeared to be a mindless beast with a taste for human flesh and the capability of breathing both underwater and on land. After they killed Coach Marin, the monsters were released to the ocean. The remaining students who also had been exposed to the steroids, such as Xander, underwent a number of treatments to reverse the process.[2]

Behind the scenes[]

  • Unidentified in the series, the episode script referred to the creature as "Gill Monster." It described: "The thing has a spiny head, like a fish; palpitating gills at the side of its neck; large cold black bulging eyes that never close. Its gaping piranha-toothed jaw widens and lets out a primal croaking screech."[1]
  • The creature bears resemblance to the Gill-man, an aquatic monster who is the titular star of the 1954 horror sci-fi film Creature from the Black Lagoon.