This is a sfx Alien Warrior hero head mask from the 2004 sci-fi mashup Alien vs. Predator. This piece would have been worn by a performer in a full Alien suit to get the full range of motion, with puppeteers controlling the actual facial movements. This head was used in the film when a Predator shoots a net on an unsuspecting lunging Alien; the net is then shown digging into the Warrior's head as it tries to free itself, making it ooze acidic blood in a grid-shaped pattern.