Pack animal shortly trails behind, like this (2,7)
I believe the answer is:
as follows
'this' is the definition.
Both the answer and definition are adverbs.
Perhaps there's a link between them I don't understand?
'pack animal shortly trails behind like' is the wordplay.
'pack animal' becomes 'ass' (I've seen this in another clue).
'shortly' means to remove the last letter.
'trails' is a charade indicator (letters next to each other) (some letters follow or trail others).
'behind like' becomes 'follows' (I can't justify this - if you can you should believe this answer much more).
'ass' with its last letter taken away is 'as'.
'as'+'follows'='AS FOLLOWS'
Can you help me to learn more?
(Another definition for as follows that I've seen is " what is listed next".)