Silly Bandz, once (3)
I believe the answer is:
fad
'silly bandz once' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for fad that I've seen before include "'Craze, all the rage (3)'" , "A craze, usually passing" , "A passing liking or fashion" , "Caprice" , "Passing vogue or fashion" .)