Fluctuate like a toy (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 toy' is the second definition.
(I've seen this before)
'like' is the link.
(Other definitions for yo-yo that I've seen before include "Toy made to rise and fall on string" , "Ma perhaps" , "Toy (with ups-and-downs!)" , "Fluctuate repeatedly" , "-- - -- Ma, American cellist of Chinese/French origins" .)