Something afoot that sounds frightening to cats, etc. (4)

I believe the answer is:

shoe

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

I can't explain the rest of the clue.

(Other definitions for shoe that I've seen before include "Hose (anag)" , "From which playing cards are dealt one at a time" , "Footwear - playing-card dispenser - part of a brake" , "mule, perhaps?" , "Clothing item" .)

I've seen this clue in the Evening Standard.

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