Ponies lone wolf disturbed all at the same time (2,3,4,5)

I believe the answer is:

in one fell swoop

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'all at the same time' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'ponies lone wolf disturbed' is the wordplay.
'disturbed' indicates anagramming the letters (the order of letters is disturbed).
'ponies'+'lone'+'wolf'='ponieslonewolf'
'ponieslonewolf' is an anagram of 'IN ONE FELL SWOOP'.

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I've seen this clue in The Guardian.

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