Calamity of the Zombie Girl

The anime Calamity of the Zombie Girl centers around five university students who sneak into a library storage room on a summer day. They discover two Italian mummies, dating back to around 14-20 years old, and one of the students, Sayaka, removes the "stone of life" from a mummy's wrapping. This stone granted the mummies superhuman strength and immortality, but taking it reanimates the mummies as zombies, driven to reclaim their lost power.