Somehow made realities disappear (13)
I believe the answer is:
dematerialise
'disappear' is the definition.
('disappear'->'dematerialize' is in my internal thesaurus and 'ize'->'ise')
'somehow made realities' is the wordplay.
'somehow' indicates anagramming the letters.
'made'+'realities'='maderealities'
'maderealities' is an anagram of 'DEMATERIALISE'.
(Other definitions for dematerialise that I've seen before include "Cease to have physical presence" , "Vanish" , "Lose physical presence" .)