Shaking, Brad Pitt detailed hallucinogenic nightmare (3,4)

I believe the answer is:

bad trip

I'm a little stuck... Click here to teach me more about this clue!

'hallucinogenic nightmare' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'shaking brad pitt detailed' is the wordplay.
'shaking' is an anagram indicator.
'detailed' means to remove the last letter (the tail of the word is removed).
'brad'+'pitt'='bradpitt'
'bradpitt' with its final letter removed is 'bradpit'.
'bradpit' is an anagram of 'BAD TRIP'.

Can you help me to learn more?

(Another definition for bad trip that I've seen is " problem with horse?".)

I've seen this clue in The Telegraph.

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