Animals run away, first to last (4)
I believe the answer is:
cats
'animals' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
(Other definitions for cats that I've seen before include "Siamese, Persian etc" , "Show" , "Musical (felines?)" , "Spectacular Llyod Webber feline musical" , "Musical; animals" .)