Demon drink for Spike (6)
I believe the answer is:
impale
'for spike' is the definition.
(synonyms)
'demon drink' is the wordplay.
'demon' becomes 'imp' (I've seen this before).
'drink' becomes 'ale' (type of beer).
'imp'+'ale'='IMPALE'
(Other definitions for impale that I've seen before include "Skewer" , "Pierce with a sharp stake" , "Pierce with pointed stick" , "Transfix, pierce (with a sharp instrument)" , "Transfix with spear" .)