Hate transforming into a beam (9)
I believe the answer is:
abominate
'hate' is the definition.
(abominating is a kind of hating)
'transforming into a beam' is the wordplay.
'transforming' is an anagram indicator (I've seen this in other clues).
'into'+'a'+'beam'='intoabeam'
'intoabeam' anagrammed gives 'ABOMINATE'.
(Other definitions for abominate that I've seen before include "Dislike deeply" , "Be revolted by" , "Hate" , "Loathe, detest" , "Loathe, find hateful" .)