The worm

I heard if you soak Wormwood in Pernod for a month it becomes absinthe.

 

You will get something that might be bitter and it might be greenish, but it won't be absinthe.
Pernod is 40% alcohol and real Absinthe is about 70%. This difference affects what is extracted.
It will also depend on the temperature, how finely you chop the wormwood up and do you just use leaves or leaves and stems.
I would still want it analysing before drinking it.
Best bet would be to treat yourself to a bottle of Pernod Absinthe at 68% alcohol or one of the other proper Absinthes available in the UK.

 

Right. Thank you very much.