A Colorado man was killed by his illegal pet Gila monster’s venom, according to an autopsy report—the first such fatality in nearly a century. Christopher Ward, 34, and his girlfriend bought Winston and another Gila monster named Potato at a reptile show in October, according to the Associated Press. In February, Winston bit Ward’s hand with immediate consequences: vomiting, loss of consciousness, and difficulty breathing. The animal’s bites are not usually fatal, but by the time Ward got to a hospital—he waited two hours to call an ambulance—he was in dire condition and suffered several seizures before dying. It’s believed that Winston latched onto Ward’s hand for four minutes. “They bite, they hold on, and they chew, and that’s how they deliver their venom,” Kevin Torregrosa, curator of herpetology at the Bronx Zoo, told The New York Times. Ward had underlying medical conditions that contributed to his death, the autopsy found.