Band to stare wildly at king (6)
I believe the answer is:
streak
'band' is the definition.
(I have seen 'Long band' mean 'streak' so perhaps 'band' could also mean 'streak')
'stare wildly at king' is the wordplay.
'wildly' is an anagram indicator.
'at' is a charade indicator (letters next to each other).
'king' becomes 'k' (abbreviation for king in chess).
'stare' with letters rearranged gives 'strea'.
'strea'+'k'='STREAK'
'to' acts as a link.
(Other definitions for streak that I've seen before include "Race" , "Run very fast" , "Long mark, run swiftly" , "Move very fast; thin strip" , "Long band" .)