Curse of the Mummy follows Rain Man occasionally (8)
I believe the answer is:
anathema
'curse' is the definition.
(anathema can mean a curse)
'the mummy follows rain man occasionally' is the wordplay.
'mummy' becomes 'ma' (both can mean a mother).
'follows' means one lot of letters go next to another.
'occasionally' indicates alternate letters.
'rain'+'man'='rainman'
The alternate letters of 'rainman' are 'ana'.
'the'+'ma'='thema'
'thema' after 'ana' is 'ANATHEMA'.
'of' is the link.
(Other definitions for anathema that I've seen before include "person cannot stand" , "hated person" , "Curse; object of loathing" , "It's detested or abhorred" , "Person or thing that's abhorred" .)