Legendary animal makes RC union wobble (7)
I believe the answer is:
unicorn
'legendary animal' is the definition.
'unicorn' can be an answer for 'animal' (I have seen 'Mythical animal' mean 'unicorn' so perhaps 'animal' could also mean 'unicorn'). I'm not sure about the 'legendary' bit.
'rc union wobble' is the wordplay.
'wobble' is an anagram indicator (letters wobble around).
'rc'+'union'='rcunion'
'rcunion' is an anagram of 'UNICORN'.
'makes' is the link.
Can you help me to learn more?
(Other definitions for unicorn that I've seen before include "Mythical white animal with long horn" , "that's fabulous" , "Team of three" , "Mythical one-horned creature" , "Representative of Scotland" .)