I have a PC who insists on smoking "dreadweed" every chance he gets (and generally acting like a stoner). It has been established in the campaign that this is a pot-like herb which can be smoked or mixed into food. It has somewhat mild effects like pot, although it can also cause hallucinations as powerful as a phantasmal force. Behaviorally, the character acts like Cheech and Chong, Bill and Ted, the guys on "Dark Star", etc. He's also always trying to push it on NPCs or sneak it into their food.
The player is so into it he thinks his wizard should get special magical abilities from it and wants to design a prestige class around it. OTOH I (the GM) think there should be some detrimental effect, plus I'm getting tired of the "stoner" silliness, but I don't know enough about pot to really say what it does to you.
Some things I've done in the game is draining a few points of wisdom, inflict hallucinations, having spells misfire or have unexpectedly powerful results, have the character spontaneously levitate when very stoned, lose interest in whatever he's doind and stand there in a stupor, etc.
So, what effect would pot smoking have in D&D terms? Would it affect initiative? AC? Spell memory?
Also, what magical effects might it have? I'm looking for ideas here.
Thanks,
Mike