The standard Graboid is the only creature to have appeared in all four entries, and also the 2003 TV series of the same name. There are two known species: one in North America and the other in Africa. in both species, the Graboid is the first stage in the creatures' life cycle. In Tremors 4: The Legend Begins, which is a prequel taking place in 1889, thus before they got their current name, they are referred to as "dirt dragons". The name "Grabboid" was invented by the shop owner character in the first film, Tremors, Walter Chang; who was subsequently eaten by one. Some of the other names that were considered for the Graboid by Melvin and Walter included "Snakeoids", "Suckers", "Suckoids" or "Mega-Worms". Promotional material written by the Sci Fi Channel classifies them as Devonian Era invertebrate predators, possibly Cephalopods.