High Quality Content by WIKIPEDIA articles! The Beaded lizard (Heloderma horridum) is a species of venomous lizard found principally in Mexico and southern Guatemala. Along with its congener, the Gila monster (Heloderma suspectum), it is the only lizard to have evolved an overt venom delivery system, and has long been considered the only venomous lizard. The beaded lizard is larger than the Gila monster but has duller coloration, black with yellowish bands of differing width depending on the subspecies. A specialized predator that feeds primarily upon eggs, the primary use of its venom is still a source of debate among scientists. However, this venom has been found to contain several enzymes useful for manufacturing drugs in the treatment of diabetes, and research on the pharmacological use of its venom is ongoing.