Parasite in cake? (6)
I believe the answer is:
sponge
I believe this is a double definition.
'parasite' is the first definition.
(term for someone getting something from others)
'cake?' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for sponge that I've seen before include "Bum - cleaner" , "Absorbent cleaner - cadge" , "Porous substance to absorb liquid" , "Ask for money" , "Marine creature - cadge" .)