Mr Universe repeatedly lifts small submarine, perhaps (6)
I believe the answer is:
sarnie
'submarine perhaps' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'mr universe repeatedly lifts small' is the wordplay.
I cannot really see how this works, but
'mr' could be 'arnie' and 'arnie' is found within the answer.
'small' could be 's' (abbreviation - e.g. clothes size) and 's' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sarnie that I've seen before include "Two slices of bread with a filling" , "Sandwich (informal)" , "no classy fare" , "Sandwich (slang)" , "Popular bread-based snack (colloq)" .)