Copper, special originally, eating something done that's succulent (6)
I believe the answer is:
cactus
'succulent' is the definition.
(cactus is a kind of succulent)
'copper special originally eating something done' is the wordplay.
'copper' becomes 'cu' (chemical symbol).
'originally' suggests taking the first letters.
'eating' indicates putting letters inside.
'something done' becomes 'act' (I've seen this before).
The initial letter of 'special' is 's'.
'cu'+'s'='cus'
'cus' enclosing 'act' is 'CACTUS'.
'that's' acts as a link.
(Other definitions for cactus that I've seen before include "Prickly desert plant" , "Spiky desert plant" , "Eg, prickly pear" , "Spiney plant of dry areas" , "Often prickly succulent plant native to arid regions" .)