Kay's chat surprisingly involves pile of dried grass (8)
I believe the answer is:
haystack
'pile of dried grass' is the definition.
(I've seen this before)
'kay's chat surprisingly' is the wordplay.
'surprisingly' indicates anagramming the letters (a surprising ordering of the letters).
'kays'+'chat'='kayschat'
'kayschat' is an anagram of 'HAYSTACK'.
'involves' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for haystack that I've seen before include "Pile of cut grass" , "Large mound of dried grass" , "Pile of dried grass" , "Large pile of fodder" , "Rick of dried grass" .)