Watch a pet unravelling ribbon (6,4)
I believe the answer is:
ticker tape
'ribbon' is the definition.
(thesaurus)
'watch a pet unravelling' is the wordplay.
'watch' becomes 'ticker' ('ticker' can be a synonym of 'watch'**).
'unravelling' indicates anagramming the letters.
'a'+'pet'='apet'
'apet' is an anagram of 'tape'.
'ticker'+'tape'='TICKER-TAPE'
(Other definitions for ticker tape that I've seen before include "Traditional kind of New York parade to welcome a visiting dignitary" , "Paper thrown in US celebrations" , "such a procession" , "Sort of welcome" .)