Some riot terrifying animal (5)

I believe the answer is:

otter

'animal' is the definition.
(I've seen this before)

'some riot terrifying' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'OTTER' is hidden within 'riot terrifying'.

(Other definitions for otter that I've seen before include "River-dwelling mammal" , "Aquatic creature" , "River animal" , "Something furry" , "Aquatic beast" .)

I've seen this clue in The Daily Express.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.