Abracadabra, HP and couscous! Horrible! (5-5)
I believe the answer is:
hocus-pocus
'abracadabra' is the definition.
(thesaurus)
'hp and couscous horrible' is the wordplay.
'and' is a charade indicator (letters next to each other).
'horrible' indicates anagramming the letters.
'hp' after 'couscous' is 'couscoushp'.
'couscoushp' anagrammed gives 'HOCUS-POCUS'.
(Other definitions for hocus-pocus that I've seen before include "Conjurer's incantation" , "Mumbo-jumbo" , "Conjuror's incantation" .)