Aussies often make jokes about burning down the house when they come across giant spiders, but one American may have done just that.
Tucson firefighters suspect a resident used a propane blowtorch to burn spiders and spiderwebs from under the mobile home, before it went up in flames.
The Tucson Fire Department is still investigating the official cause of the blaze.
Fire crews arrived at 9.30pm on Sunday and were able to contain the flames to just the single home, where the fire caused serious damage, Oregon news service KPTV reported.
An elderly woman sustained minor injuries when she was carried out of the caravan by her son with the help of neighbors, the Tucson Fire Department confirmed.
She was treated by paramedics at the scene and no other injuries were reported.