Numbers at horrible endless feature film (9)
I believe the answer is:
nosferatu
'film' is the definition.
(1922 vampire film)
'numbers at horrible endless feature' is the wordplay.
'numbers' becomes 'nos' ('no' is an abbreviation for number).
'at' says to put letters next to each other.
'horrible' is an anagram indicator.
'endless' means to remove the last letter.
'feature' with its last letter removed is 'featur'.
'featur' anagrammed gives 'feratu'.
'nos'+'feratu'='NOSFERATU'
(Other definitions for nosferatu that I've seen before include "F.W. Murnau's early Dracula film" , "Old film" , "1922 Dracula film" , "horror film" .)