The Potion of Poison (II) inflicts a stronger Poison effect for 21 seconds, causing faster health reduction without killing the target. It is brewed by combining a Potion of Poison (0:45) with Glowstone Dust in a Brewing Stand. This enhanced version is highly effective for quickly weakening enemies in combat, but it remains ineffective against undead mobs like Zombies and Skeletons, which are immune to Poison. Use it strategically to maximize its impact in battles.