Blue's Clues cut episode's beginning and ran wild (8)
I believe the answer is:
cerulean
'blue's' is the definition.
(cerulean is a kind of blue)
'clues cut episode's beginning and ran wild' is the wordplay.
'cut' means to remove the last letter.
'beginning' indicates taking the first letters.
'and' says to put letters next to each other.
'wild' indicates anagramming the letters.
The initial letter of 'episodes' is 'e'.
'clues' with its last letter removed is 'clue'.
'clue'+'e'+'ran'='clueeran'
'clueeran' is an anagram of 'CERULEAN'.
(Other definitions for cerulean that I've seen before include "Light shade of blue" , "Sky-blue for Laurence" , "of clear heavenly appearance" , "Deep blue colour" , "Sky-blue in literary way" .)