Bring about one of those special illusions? (6)
I believe the answer is:
effect
'bring about' is the definition.
(synonyms)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for effect that I've seen before include "Result; make happen" , "Grounds for an act" , "See 7" , "'Result, consequence (6)'" , "Meaning < to force" .)