Might add a little chaos to the game, with effects from all existing potions plus a couple of new effects exclusive to them.

Could be a blazing speed potion, a HP potion, or ruggedizer (hell, even werewolf spit could be an option, that's technically a potion?)

A corresponding skill might be able to identify them down the road, turning them into a random regular potion, but for now it might break up grinding sessions with a bit of chaos for brave souls; maybe you'll chug a minor panacea down, curing that pesky curse, or maybe you'll end up blowing yourself up?