Viper Bottle

The Viper Bottle is a consumable that deals 5 damage to the user and permanently raises one random stat by 1.

The stat gained is random and permanent, meaning it persists for the rest of the run regardless of equipment changes. The 5 damage cost is fixed and not reduced by armor or resistances, so it requires the character to have sufficient HP to absorb the hit safely. Unlike stat-boosting equipment, the Viper Bottle's benefit cannot be stolen or removed by debuffs.

Best used on high-HP characters who can easily absorb the self-damage cost, or after healing to ensure you are not dangerously low. Because any stat can improve, the value is somewhat lottery-like — but even a random +1 to a useful stat is a free permanent boost worth taking on a healthy character. If you can find multiple copies, stacking them on a tank or primary damage dealer is a strong long-game investment.