Renegade Reptiles are short, bipedal creatures, covered in dark-red scales. Their arms and legs ends in small, sharp claws, and their heads are decorated with an array of long, thin horns. They have narrow snouts and yellow eyes, and they wear a sleeveless top and shorts. They wield a large scimitar in one hand, and a smaller, curved knife in the other. They wear bandages around their wrists.
The hand they hold each of their weapons in changes depending on from which angle they approach the player and their Vulpin. If they approach from the left, the scimitar will be held in their left hand and their knife in the right; if they approach from the right, the opposite is true.
The Renegade Reptile is capable of using only the damage-dealing Attack and Flame Strike. It lunges forward and swings it scimitar down on its target to deal damage. When attacking, it never seems to need to use its smaller knife, and relies purely on its scimitar for battle.
- The name Renegade Reptile comes from Renegade, meaning "a person who leaves a cause for another" or "traitorous", and Reptile, a reference to this creature's lizard-like appearance.
- Due to its head structure bearing a strong resemblance to that of the Flaming Fossil, it can easily be speculated that the death of a Renegade Reptile results in a Flaming Fossil being born.