Teenagers Battle the Thing (1958)

Archaeologist Dr. Bill Wyman takes five high school students and their teacher to an ancient Indian campsite. While there, a strange stone tool prompts them to explore a high ledge above its finding place. This leads to the discovery of a stone tablet sealing the entrance to a cave. As it is levered open, white fumes erupt. Inside they find a mummified corpse that is plastered in mud. The mummy is brought back to a shed at their lodging. Free of the fumes, it emerges from thousands of years of dormancy. It wanders through citrus groves to a nearby ranch where it kills a young woman. The local sheriff joins the group to track down the creature before it can kill anyone else. They are armed with gasoline and flares.