Intergalactic visitors' short answer involved fib (6)
I believe the answer is:
aliens
'intergalactic visitors' short answer involved' is the definition.
I can't judge whether this defines the answer.
'fib' is the wordplay.
I cannot really understand how this works, but
'fib' could be 'lie' (a fib is a lie) and 'lie' is located in the answer.
The remaining letters 'ans' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for aliens that I've seen before include "Outer space creatures, perhaps from Mars?" , "Outsiders" , "Extra-terrestrial beings" , "'Little green men'?" , "Strangers, extraterrestrials" .)