Dozens of mischievous creatures chasing short couple (7)
I believe the answer is:
twelves
'dozens' is the definition.
('twelve' can be a synonym of 'dozen')
'mischievous creatures chasing short couple' is the wordplay.
'mischievous creatures' becomes 'elves' (I have seen 'Supernatural creatures ' mean 'elves' so perhaps 'creatures' could also mean 'elves'. I am not sure about the 'mischievous' bit.).
'chasing' is a charade indicator (letters next to each other) (some letters chase after others).
'short' means to remove the last letter.
'couple' becomes 'two' (two people or things).
'two' with its final letter taken away is 'tw'.
'elves' put after 'tw' is 'TWELVES'.
'of' is the link.
Can you help me to learn more?
(Another definition for twelves that I've seen is " numbers".)