Fluctuate like a plaything (2-2)
I believe the answer is:
yo-yo
This clue is a double definition.
'fluctuate' is the first definition.
(I've seen this before)
'a plaything' is the second definition.
(yo-yo is a kind of plaything)
'like' is the link.
(Other definitions for yo-yo that I've seen before include "Child's toy on a string" , "Ma perhaps" , "Toy made to rise and fall on string" , "Move up and down" , "An up-and-down toy on a string" .)