Sponge transformed rugs once (8)
I believe the answer is:
scrounge
'sponge' is the definition.
(I've seen this before)
'transformed rugs once' is the wordplay.
'transformed' indicates an anagram.
'rugs'+'once'='rugsonce'
'rugsonce' with letters rearranged gives 'SCROUNGE'.
(Other definitions for scrounge that I've seen before include "Cadge, sponge" , "bum" , "Try to get hold of" , "Cur's gone (anag) - beg" , "Cadge, beg" .)