Rich source of malevolent spirits causing collapse? (7)
I believe the answer is:
implode
'collapse?' is the definition.
(imploding is a kind of collapsing)
'rich source of malevolent spirits' is the wordplay.
I cannot really understand how this works, but
'source' could be 'lode' (I have seen 'Rich source' mean 'lode' so perhaps 'source' could also mean 'lode') and 'lode' is found within the answer.
The remaining letters 'imp' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'causing' acts as a link.
(Other definitions for implode that I've seen before include "Cause to burst inwards" , "Collapse suddenly inwards" , "Burst inward" , "Violently collapse inwards" .)