Not every potion will make you shrink, Alice.

 

 

Unexpected Side-Effect of Consuming this Unknown Substance
d20
1Random Mutation.
2Your skin turns a mottled purple, like a spreading rash, over time it loses its elasticity and grows more than it should, forming wrinkled folds.
3You hear hundreds of voices talking over each other in your head for the next d4 Turns. The thoughts of the people around you are in there somewhere.
4It was full of the eggs of some parasitic insect. The next time you're in a crowd of people make an Intelligence check to resist the urge to embrace the nearest person in an open-mouthed kiss as you regurgitate larvae down their throat to start the next development cycle. They need to be passed on three times to reach maturity. If you resist, the larvae will die and pass out of your system.
5Everything but your circulatory system seems to dissolve into invisibility. You can see things crawling through the space where your flesh should be.
6Your mind goes into overdrive, flooded with possibilities. For the next hour gain a d6 bonus to each knowledge check, save, and to-hit roll. After an hour you lose consciousness for d4 Turns, with a 20% chance of gaining a random Insanity, and a 10% chance of gaining permanent knowledge of a new spell, regardless of class.
7Your gender changes, but not very well.
8You reek of rotting meat for the next d4 days.
9For the next d4 days any wounds that don't kill you outright heal d6hp/Round, flesh knitting before the eyes of your bewildered foes. When the effect ends there is a percentage chance equal to hp healed that your old wounds continue healing at an accelerated rate, developing bulbous cancerous growths. If they are allowed to grow to the size of a fist they will contain a luminous green gem like a cluster of bubbles.
10You develop extreme photosensitivity for the next 2d4 days; spending more than an hour in direct sunlight causes steam to rise from your broiling skin, I wouldn't push it.
11The bones in your arms become soft and elasticised for d4 Turns, hanging down below your knees. They still function but it's hard to move anything but your hands, you kind of need to swing them in the right direction.
12Scent of Fear. For the next day you exude pheromones that trigger danger signals, that mark you as an alpha predator. Animals will not attack you unless desperate, you gain appropriate bonuses to intimidation, and intelligent beings attacking you in melee must make an Intelligence check to swallow their panic.
13Fertile Fields. Small plants and fungus sprout from your skin, it's fucking painful. Soon your back and shoulders look like rainforest undergrowth.
14You start seeing a cherub with bored-out black hole eyes floating around you, but it doesn't exist for anyone else. The more you talk to it the more it is able to interact with reality.
15Your teeth blacken and fall from your shrunken gums, your tongue burns as it splits like a dividing worm and stretches to twice its original length.
16Neurons fire and multiply like catastrophic culture in a Petri dish, latent telesthesia manifests and small puckered holes open around your skull, venting thin vaporous streams. For d4 days you are able to implant irresistible mental suggestion or alter memory and perception in others simply by rolling under your Intelligence; if you wish to force them do something unthinkable or open an imploding pocket of nothingness inside their grey matter they may save vs. Poison.
When the duration ends the subsiding electrical fever will cause a deterioration that permanently decreases your Intelligence by double the duration. In your heightened mental state you know this will happen. You also know that the only way to prevent the cerebral decay is to consume the brain of someone who trusts you implicitly.
17Nothing special, you are just intoxicated, but it is a very good intoxication.
18Your organs liquefy and leak out but you don't mind, because they are being replaced by new ones, new ones that are alive all by themselves and whisper within the cavities of your flesh and heal you and will never let you die, no matter how many times you are mangled and torn apart, no matter how much your mind begins to slip away from you, no matter how hard you cry and beg for it to all just end, they will never let you die.
19Spilt bodily fluids take on an ethereal phosphorescent glow, marking trails and inciting awkward copulatory conversations. They are also highly flammable. Putting out a match on your tongue would conflagrate your head.
20A Cure for Unhealthy Bibliophilic Tendencies. Touching books causes your skin to crawl, a burning itch that swells up from the palms of your hands, reading more than a few lines brings tears of near pure salt to your eyes, and soon the musty smell alone of a time-worn tome causes you to spill your stomach across the floor.