Much is unknown about Garthoks. Though these creatures has talons and sharp teeth, it did spit out pieces of the Remulakians that it killed, possibly indicating that it is a vegetarian (or just did not like Conehead flesh). The former is in keeping with some giant Earth vegeratian herbivorous creatures, such as rhinos and hippos, which are known for their ferocity and short tempers. The creature had the same blue blood as a Remulakian, and had a high pitched roar that was nowhere near as loud or as impressive as would be expected from such a vast creature. It is strong enough to tear apart a Remulakian, which, as seen by Beldar, are strong enough to punch through walls, stop a car from driving off using just one hand, and tearing into the metallic roof of a car one handed. Considering this, and the fact that they are native to Remulak, Garthoks may be far stronger than megafauna animals on planet Earth (hippopotamuses, elephants, rhinoceroses, etc.) just as Remulakians are far stronger than human Earthlings.
In the film, Beldar Conehead slew the creature by striking a golfball with his sickle weapon, which shot into the creature's mouth and then throat, choking it to death. Later, in a brief scene, one can see the severed head of the Garthok, and Beldar covered in blue Garthok blood.