Explosive found on beach (5)
I believe the answer is:
shell
'on beach' is the definition.
The answer and definition can be both natural objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'explosive' is the wordplay.
I cannot quite see how this works, but
'explosive' could be 'he' (abbreviation for high explosive) and 'he' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'found' is the link.
Can you help me to learn more?
(Other definitions for shell that I've seen before include "Conch, perhaps" , "bomb?" , "pepper?" , "cover" , "Hull" .)