Santo in the Vengeance of the Mummy(1971)

Original title: Santo en la venganza de la momia

When Santo accompanies a troupe of archaeologists in the search for Aztec artifacts, they find the Mummy of an Aztec who leaves a warning to those who tamper with his resting place. The adventurers ignore the warning, and before long, the Mummy starts bumping them off one-by-one with his bow & arrow.