Abnormally formed animal in gym — on steroids! (7)
I believe the answer is:
monster
'abnormally formed animal' is the definition.
'monster' can be an answer for 'animal' (I have seen 'Hideous animal ' mean 'monster' so perhaps 'animal' could also mean 'monster'). I am not certain of the 'abnormally formed' bit.
'in gym on steroids' is the wordplay.
'in' says the answer is hidden in the clue.
'MONSTER' can be found hidden inside 'gym on steroids'.
Can you help me to learn more?
(Other definitions for monster that I've seen before include "something large and ugly" , "Fabulous creature" , "Imaginary beast" , "Large, ugly and frightening imaginary creature" , "Ugly and frightening beast as in 8 Across" .)