Muscular alien has self-serve meal (6)
I believe the answer is:
buffet
'self-serve meal' is the definition.
(I've seen this in another clue)
'muscular alien' is the wordplay.
'muscular' becomes 'buff' (I've seen this in another clue).
'alien' becomes 'et' (extra terrestrial).
'buff'+'et'='BUFFET'
'has' is the link.
(Other definitions for buffet that I've seen before include "Refreshment counter - slap" , "Kind of meal where guests serve themselves (6)" , "Box" , "Variety of restaurant" , "Help yourself table" .)