Mine would be arbitrarily slowing down a character to maintain horror in a game. I get if there are reasons like age, injury, or location that could provide context, but don't turn my legs into molasses because you need to time the jump scare just right.
They only work in an actual survival game like Minecraft where you have to eat food, and even then, potions are kinda silly (but there are a bunch of cool ones like the speed boost, night vision, and fire resistance). I feel like most games just don't have a big enough loss from death to bother with them. Playing Witcher 3 and I've basically never used potions or whatever outside of required quest items. There's too many, they're too specific, and if you die you just reload a save and attack enemies in a different way. In other words, the only good consumables are ones that restore your health.