Harpies gallivanting about, like other mythical creatures (8)
I believe the answer is:
seraphic
'like other mythical creatures' is the definition.
'harpies gallivanting about' is the wordplay.
'gallivanting' indicates an anagram (I've seen this in other clues).
'about' becomes 'c' (abbreviation for 'circa').
'harpies' is an anagram of 'seraphi'.
'seraphi'+'c'='SERAPHIC'
(Other definitions for seraphic that I've seen before include "To do with top angels" , "Angelic" , "serene" , "Like the highest ofder of angels" .)