Isso provavelmente é The Faculty . Do resumo da Wikipedia :
Casey returns to the gym, where Marybeth reveals herself to be the queen, having faked taking the test earlier. She attacks Stokes, who is stunned at the revelation. Casey and Stokes flee to the swimming pool where Stokes is injured and infected. Zeke and Casey go to the locker room, where Marybeth reverts to her human disguise, naked. She explains that she is taking over Earth because her own planet is dying. Marybeth transforms back to the queen and renders Zeke unconscious by throwing him into a locker. Casey takes the drug and tricks the queen into following him into the retracting bleachers, thus trapping her. Casey then stabs the drug into the queen's eye to kill it.
