The Faculty is an Earth based science fiction which was released in 1998 and is directed by Robert Rodriguez.
The premise of the story is that teachers have been taken over by an alien from another planet. A lot of school children will empathise with it. All what stands between the aliens and conquering the planet is a group of high school children led by Casey Connor. Unbeknown to them, the lead alien is amongst the group.
Casey Connor ( Elijah Wood )
Casey is one of the student at the high school that has been infiltrated by an alien. He is the main protagonists in the film, trying to keep one step ahead of the aliens that are led by Marybeth Hutchinson