leviathan - the largest or most massive thing of its kind; "it was a leviathan among redwoods"; "they were assigned the leviathan of textbooks"

mutant, mutation, sport, variation - (biology) an organism that has characteristics resulting from chromosomal alteration

enthusiast, partizan, partisan - an ardent and enthusiastic supporter of some person or activity

gym rat - someone who spends all leisure time playing sports or working out in a gymnasium or health spa

panic - be overcome by a sudden fear; "The students panicked when told that final exams were less than a week away"