What does the cryptic crossword clue "Abnormally formed animal in gym — on steroids! (7)" mean?

The definition is "steroids!". The wordplay uses a hidden word. Hidden in "abnormally formed animal in gyM — ON STERoids!" The answer is MONSTER.

Abnormally formed animal in gym — on steroids! (7)

Times Cryptic #28950 | 17 Down | 2024-06-22 flower