More than one abominable snowman still exists (5)
I believe the answer is:
yetis
'more than one abominable snowman' is the definition.
'still exists' is the wordplay.
'still' becomes 'yet' (yet can mean still or so far).
'exists' becomes 'is' (if something 'is', it exists).
'yet'+'is'='YETIS'
(Other definitions for yetis that I've seen before include "Mythical creatures" , "More than one mythic creature" , "fantastic beasts" , "Mountain monsters" , "Abominable snowmen" .)