Chiroptera.

A trio of friends drunkenly explores an abandoned school building. After breaking in, Dahlia dares Blair to go into the basement, where she stumbles upon a large bag with something bloody inside. Blair attempts to warn the others, but Foster's ego forces him to investigate. Soon, they realize they are not alone as a creature lurks in the shadows. Trapped, Dahlia and Blair are forced to fight the creature to survive. In the aftermath, Blair begins to feel something dark within.