Essence Of Dragon Bile
Please substitute whatever obscure carcass is convenient for your campaign. In my example, the bile resides inside the dragon's gall bladder, pretty easy for non-experts to miss.
In order to prepare the bile for use, the wizard must extract its essence. This is done within a special kiln costing no less than 100 gold, which must burn for three days straight while the bile simmers within a sealed clay sphere. During this time, the bile reduces to less than an ounce of liquid (the waste materials glaze onto the interior of the sphere). Any flaw in the kiln or sphere will result in the total loss of materials involved and force the wizard tending the fire to make a save against leukemia.
The kiln is an awful thing. It smells bad, poisons small animals, kills nearby vegetation, and pollutes bodies of water within a fifty foot radius. Even when not in use, kiln bricks that have seen use emit an unsavory glow.
A Bilious Concoction
After extraction, the essence of dragon bile is rushed through a series of breakneck alchemical processes: it is mixed with a tincture of nightshade and esphand seeds; vitreous humors from beetles are added and subtracted; finally, turquoise dust is dissolved in it and the whole substance is allowed to crystallize.
Any exposure to fire during this process will cause the liquid to explode, scattering deadly shards of glass and burning goop. At several critical junctures, the chemicals are unstable enough that even light (especially magical light) will cause them to combust. The wizard must navigate these alchemical crossroads in total darkness. Should the matter combust, treat it as a fireball cast by a 5th-level wizard, but with more property damage.
Even after completing the process, the alchemist must avoid others for 1d6 days afterwards, for during this time they suffer from a residual curse that inflicts 1 damage per round on any creature that they lay eyes upon, out to about a hundred feet. Such individuals feel that a wicked spirit is tormenting them and intuit that the wizard is the cause.
The Delicious Effects
The exact effects of wizard meth vary from batch to batch, but it always includes a weeklong spate of egomaniacal euphoria. During this time, the wizard cannot sleep. Indeed, they are immune. Though they cannot rest to recover spells, the wizard meth allows them to recover expended spells at a rate of one per 1d4 hours (lowest-level first, skip 0th-level if that's a thing).
Several other effects can occur, as well. Each time a player makes use of wizard meth, the DM and they each choose a single effect from below:
- The range of any fireball spells cast by that wizard are doubled.
- They do not suffer falling damage. Though they leave impressive impact craters.
- They can kill one NPC with less than 10 max hp, per round, just by staring really hard. If the NPC has a name, they get a save.
- They can summon a giant bat that will carry them for about a hundred feet before they realize the wizard is way too heavy and need to put them down.
- The wizard's brain can slip out their ear and move about by its own slimy self, perceiving its surroundings via dim telepathy. The body lies mostly comatose during this time, though it may sometimes attempt the actions it knows best.
- The wizard can conjure a golden skull that skeletal undead will do anything to possess.
- The Midas touch, but centipedes instead of gold, and only affecting furniture.
- Whatever else you come up with. Write it down.
The Tail End
After the drug wears off, the wizard is listless and unable to cast their highest level of spells for a full week. Non-wizards who imbibe wizard meth get a headache so fierce that they are effectively blind for a full day. Neutralize poison fixes the latter but not the former.