Hippos sweat a red, oily substance that acts as a natural sunscreen and antibiotic. This "blood sweat" can look pretty nasty.

Kangaroos sometimes clean themselves by licking their forearms. This might seem cute until you realize they also lick their own urine to cool down.

Bats often live in large colonies, and their droppings, called guano, can pile up and become a breeding ground for bacteria and fungi.

Rats can squeeze through incredibly small spaces, often leaving behind greasy smears from their fur, which is coated in oils and dirt.

Elephants use their trunks to blow snot and dirt out of their nostrils, which can be quite a messy affair.

Vultures have a unique way of cooling down: they urinate on their legs. This practice helps them stay cool but leaves them with smelly, dirty legs.

Penguins often projectile poop to keep their nests clean. This can create quite a mess around their nesting areas.

Owls regurgitate pellets containing the indigestible parts of their prey, like bones and fur. These pellets can pile up and create a pretty disgusting scene.

Seagulls are known to vomit as a defense mechanism. If threatened, they will regurgitate their stomach contents to deter predators.

Pigeons produce a substance called "pigeon milk" to feed their young. This milk is actually a regurgitated, semi-digested food mixture.

Komodo dragons have mouths teeming with bacteria. When they bite their prey, the bacteria can cause severe infections, leading to a slow and painful death.

Snakes often eat their prey whole, and if they can't digest it, they will regurgitate it in a slimy, partially digested mess.

Turtles sometimes eat their own feces to reabsorb nutrients. This behavior, called coprophagy, is not uncommon in the animal kingdom.

Crocodiles can go months without eating, but when they do, they often consume their prey in one go, leading to bloated, rotting carcasses in their stomachs.

Geckos can shed their tails when threatened, leaving behind a wriggling, bloody stump that can be quite unsettling to witness.

Frogs can vomit their entire stomachs out of their mouths to clean them. They then swallow the stomach back down, leaving it clean and ready for more food.

Salamanders can secrete a sticky, toxic substance from their skin to deter predators. This slime can be quite difficult to wash off.

Toads have parotoid glands that secrete a milky, toxic substance when they feel threatened. This substance can cause irritation and even poisoning in predators.

Caecilians, a type of legless amphibian, give birth to live young that feed on the mother's skin. The mother's skin becomes thick and nutrient-rich, providing sustenance for the babies.

Newts can regenerate lost body parts, but the process can be quite messy, with exposed tissues and fluids during the regrowth period.

Hagfish produce copious amounts of slime when threatened. This slime can clog the gills of predators, suffocating them.

Parrotfish create a mucus cocoon around themselves while they sleep to protect against parasites. This slimy cocoon can be quite unappealing.

Candiru fish are known for their parasitic behavior. They can swim up the urethras of humans and other animals, causing extreme pain and requiring surgical removal.

Blobfish have a gelatinous, slimy appearance due to the lack of muscle and the high-pressure environment they live in. When brought to the surface, they look like a melted, gooey mess.

Catfish have taste buds all over their bodies, allowing them to "taste" their environment. This means they are constantly in contact with all the gross substances in the water.

Cockroaches can live for weeks without their heads. They eventually die from starvation, but their headless bodies can continue to move and react to stimuli.

Dung beetles roll balls of feces to use as food and breeding chambers. They lay their eggs inside the dung balls, providing a nutritious meal for their larvae.

Botflies lay their eggs on other insects, which then transfer the eggs to mammals. The larvae burrow into the host's skin, causing painful, pus-filled sores.