Stupid lad! Ike to love range in optical toy (12)
I believe the answer is:
kaleidoscope
'optical toy' is the definition.
(I've seen this before)
'stupid lad ike to love range' is the wordplay.
'stupid' is an anagram indicator (in a stupid order).
'to love' becomes 'o' (love means zero in tennis).
'range' becomes 'scope' (synonyms).
'lad'+'ike'='ladike'
'ladike' with letters rearranged gives 'kaleid'.
'kaleid'+'o'+'scope'='KALEIDOSCOPE'
'in' is the link.
(Other definitions for kaleidoscope that I've seen before include "poodle is plastered with cake" , "Viewer offering reflections" , "Toy making coloured patterns" , "Device showing coloured patterns" , "ever-changing patterns" .)