It may have a striking effect at a seance (6-7)

'it may have a' is the definition.
The definition suggests a singular noun but the answer is not.

'striking effect at a seance' is the wordplay.
I cannot really see how this works, but
'striking' could be 'rapping' (rapping is a kind of striking) and 'rapping' is present in the answer.
The remaining letters 'spirit' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?