Bell on top of a mythical creature (7)
I believe the answer is:
chimera
'a mythical creature' is the definition.
(Chimera is an example)
'bell on top' is the wordplay.
'bell' becomes 'chime' (synonyms).
'on top' becomes 'ra' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'chime'+'ra'='CHIMERA'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for chimera that I've seen before include "Illusory achievement; mythical beast" , "Fantastic creation of the mind, like Greek mythical monster" , "fake image" , "figment of the imagination" , "Illusory goal; monster" .)