Gloomy Creepers are named after their sad-looking appearance. They can be dangerous in many ways because of their infamous venom stored inside a pouch in their mouth.
Gloomy Creepers do not fight players unless provoked, but rather infect animals and water sources. When they touch water, the color turns into a darker shade of blue and will look deeper than it really is. Putting some in a bucket will cause the player to have the same side affects as being attacked by a Cave Spider. Infected animals produce infected meat that has a 95% chance of poisoning whoever eats it, including dogs. The meat will have the same color, but the animal will make down-pitched noises. This makes it hard to tell whether an animal is infected or not. Gloomy Creeperss, when provoked, will charge at their target and poison them. When low in health, they explode in a cloud of venom. If there are crops growing near infected water, the crops will also become infected (example: if infected wheat is crafted into bread, it will poison whoever eats it).
Every five passive mobs there are in one area has a 10% chance of having a Gloomy Creeper tagging along. They are found in many different places, but never underground. They are hard to see in the night because of their dark colours.