Animal upset a lot of shops (5)
I believe the answer is:
llama
'animal' is the definition.
(I've seen this before)
'upset a lot of shops' is the wordplay.
'upset' is a reversal indicator.
'lot of shops' becomes 'mall' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'mall'='amall'
'amall' written backwards gives 'LLAMA'.
Can you help me to learn more?
(Other definitions for llama that I've seen before include "Long-necked woolly animal" , "Camel-like wool source" , "Load-carrier" , "S American animal related to the camel" , "Domesticated pack animal of the Andes" .)