When the Mayor of Sunnydale decided to ascend into the form of a demon it was the demon Olvikan whose form he would transform into. The ritual to ascend into Olvikan consisted of many different scheduled events…including the ingestion of many spiderlike beings from "The Box of Gavrock". Buffy and the others didn't know what to expect when the Mayor ascended as the only person to witness an ascension in existence was Anya, although he demon she witnessed ascending was Lo-Hash and the rituals were different. But after the Mayor had Faith murder a visiting professor the gang made the connection between the professor's discovery of a large dinosaur like skeleton in a lava bed in Hawaii and the demon the mayor was going to become. The local villagers near the volcano site where the skeleton was discovered made reference to the legend of Ollokai, which Giles believed to be a bastardization of Olvikan…a very old, and very large demon. Olvikan is reptilian in form, resembling a gigantic serpent with horns and a four fanged mouth. Since a lava flow seemed to be the only thing to destroy Olvikan the gang thought they were doomed…but Willow, Oz & Giles concocted an explosion that would do the job instead and the Mayor was destroyed.