Endangered Species

Endangered Species is a 2003 American science fiction horror film written and directed by Kevin S. Tenney. It follows a cop, Mike "Sully" Sullivan trying to find out who is behind a series of killings at the local gyms, eventually realising that the killer is actually an indestructible alien, who has come to make clothes out of human beings. Along the way, he teams up with Warden, also an alien who has come to earth to protect humanity. The supporting cast includes John Rhys-Davies.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.