“ A magician develops a new way to make scrolls and can sell more powerful spells for cheap. Problem is, whether the magician is aware of it or not, the spell's power comes from spirits trapped by the magic that makes the scroll. Once used to power the scroll, the spirit is driven mad by the forces that have ripped through it's being, and often develops a homicidal thirst to destroy the one who tormented it. The spell the spirit was used for may have left some residual power in the spirit to give it more abilities than it ever used to have.
Buyer beware!”
“ What if potions and tonics had negative side effects? Potions of increased strength cause violent tempers, or damage joints. What if potions of dexterity caused tremors, or palsy?
What if they were addictive, and had withdrawal symptoms?
Could someone make a bad batch? No one use the brown strength potion!”
“ What if you send the players in a dungeon that was already raided? Maybe you could have traps that are already set off, or the corpses of monsters etc.”