 Murphy finds an ice core sample believed to originate from a meteor crater , and theorizes that the sample might be 250 @,@ 000 years old . Although Bear insists on leaving , the others are concerned about infecting the outside world . When he is asked to provide a stool sample , he attacks Mulder and tries to flee . Something moves under Bear 's skin , and he dies when Hodge removes a small worm from the back of his neck . Now without a pilot , the group is informed that evacuation is impossible because of the weather . 
