Animal in fantastic leap, note (8)
I believe the answer is:
antelope
'animal' is the definition.
(I've seen this before)
'fantastic leap note' is the wordplay.
'fantastic' indicates anagramming the letters.
'leap'+'note'='leapnote'
'leapnote' with letters rearranged gives 'ANTELOPE'.
'in' is the link.
(Other definitions for antelope that I've seen before include "bounder!" , "Long-legged ruminant" , "Long-legged, graceful animal" , "Swift deer-like animal" , "One ruminating" .)