Sphynx Cat Canadian Hairless is a rare breed of cat with extremely little fur, or at most a short fuzz over its body, and no, or very short and stiff whiskers. Their skin is the color their fur would be, and all the usual cat marking patterns (solid, point, van, tabby, tortie, etc) may be found in Sphynx too. They are sometimes mistaken for Chihuahuas because of their extremely unusual and, some say, uncatlike appearance. They are extremely intelligent, extroverted, and affectionate, often cuddling with their owners, other humans, and each other.
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Aye Aye

This one is maby more weird than ugly.
Daubentonia madagascariensis is a strepsirrhine native to Madagascar that combines rodent-like teeth with a long, thin middle finger to fill the same ecological niche as a woodpecker. It is the world’s largest nocturnal primate, and is characterized by its unique method of finding food; it taps on trees to find grubs, then gnaws holes in the wood and inserts its elongated middle finger to pull the grubs out. It weighs about 2.5 kilograms, with the female weighing in slightly less (by an average of 100 grams) than males. Other than weight and sex organs, aye-ayes exhibit no sexual dimorphism of any kind. They all grow from 30-37 cm from head to body, with a 44-53 cm tail.
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Overgrown Groundhog Teeth
Without assistance this animal would have died, however lived on.

Source: Odd Animals
Babirusa

The Babirusa or pig-deer is a pig-like animal native to Sulawesi and surrounding islands of Indonesia. The babirusa has usually been classified as a single species in the genus Babyrousa, but recent work suggests that there may be several species, differentiable on the basis of geography, body size, amount of body hair, and the shape of the upper canine tooth of the male.
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Dobsonfly

The name dobsonfly refers to any species of the genus Corydalus (family Corydalidae). The most well-known of the numerous species is Corydalus cornutus, a long, dark-colored insect of North and Central America, that spends most of its life in its larval stage. The larvae of this and other species are called hellgrammites, live under rocks at the bottoms of lakes, streams and rivers, and prey on other insect larvae. Hellgrammites are used by many fishermen as bait, though this practice may stem, more than anything, from the challenge of catching a hellgramite without being bitten.
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And now some underwater ugly creatures, those are the best:
Giant Squid

Giant squid, once believed to be mythical creatures, are squid of the Architeuthidae family, represented by as many as eight species of the genus Architeuthis. They are deep-ocean dwelling animals that can grow to a tremendous size: recent estimates put the maximum size at 13 m (43 ft) for females and 10 m (33 ft) for males from caudal fin to the tip of the two long tentacles (second only to the colossal squid at an estimated 14 m (46 ft), one of the largest living organisms). The mantle is only about 2 m (7 ft) in length (more for females, less for males), and the length of the squid excluding its tentacles is about 5 m (16 ft). There have been claims reported of specimens of up to 20 m (66 ft), but no animals of such size have been scientifically documented.
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Chimaera Fish

Chimaeras live in temperate ocean floors and grow up to two meters long. Like other members of the class Chondrichthyes, chimaeras have a skeleton constructed of cartilage. Their skin is smooth and lacks scales, and their color can range from black to brownish gray. For defense, most chimaeras have a venomous spine located in front of the dorsal fin. Chimaeras resemble sharks in some ways: they employ claspers for internal fertilization of females and they lay eggs with leathery cases. They differ from sharks in that their upper jaws are fused with their skulls; they have separate anal and urogenital openings; and they lack the many sharp and replaceable teeth of sharks, having instead a few large permanent grinding tooth plates.
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Black Dragonfish

The Black Dragonfishes (Family Idiacanthidae) are long, slender fishes which live in mesopelagic to bathypelagic waters down to depths of about 2000 m. he 22 cm long specimen in the images above was sent to the Australian Museum by the Fisheries Inspectors at Eden, New South Wales.
More: amonline.net.au
Crab

Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short “tail” (Greek: brachy = short, ura = tail), or where the abdomen is entirely hidden under the thorax. They are generally covered with a thick exoskeleton, and are armed with a single pair of chelae (claws). Crabs are found in all of the world’s oceans; there are also many freshwater and terrestrial crabs, particularly in tropical regions. Crabs vary in size from the pea crab, only a few millimetres wide, to the Japanese spider crab, with a leg span of up to 4 m.
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Deep Sea Anglerfish

Anglerfish are bony fish in the order Lophiiformes, named for their characteristic mode of predation, wherein a fleshy growth from the fish’s head acts as a lure; this is considered analogous to angling. Anglerfish are both pelagic and benthic fishes of the abyss (e.g. Ceratiidae) and the continental shelf respectively. Pelagic forms are most laterally compressed whereas the benthic forms are often extremely dorse-ventrally compressed (depressed) often with large upward pointing mouths.
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Lizard Fish

Source: Mcaorals
Blob Fish
This is really some ugly fish.:)

Image source: Oceans.greenpeace.com
Viperfish

A Viperfish (genus Chauliodus) is a deepwater fish with long, needle-like teeth and hinged lower jaws. It grows to lengths of 30 to 60 centimetres (14 inches). The name viperfish is also sometimes applied to the lesser weever.
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Umbrella Mouth Gulper Eel

The pelican eel or gulper eel, discovered by Kyle Briggins, is a deep-sea fish rarely seen by humans, though the creatures are occasionally snagged in fishermen’s nets. The pelican eel’s most notable feature is its enormous mouth, much larger than its body. The mouth is loosely-hinged, and can be opened wide enough to swallow a fish much larger than itself. The pouch-like lower jaw resembles that of a pelican, hence its name. It is also sometimes referred to as the umbrella mouth gulper. The stomach can stretch and expand to accommodate large meals. The eel uses a long, whip-like tail for movement, and the end of the tail is luminous to attract prey. The pelican eel feeds primarily on fish, shrimp and plankton. It grows to about 0.61 or 1 m in length and is found in all tropical and subtropical seas at depths ranging from 900 to 8,000 m.
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Fangtooth

This is one of the most savage looking of all the deep-sea fishes. Luckily it only gets to about the size of your hand. It is related to the orange roughy and redfish. It is a mid-water species that feeds on fish using large fangs to seize its prey. The two biggest teeth in the bottom jaw are so large that when the mouth closes, these teeth slide into sheaths in the roof of the mouth that pass either side of the fish’s brain. It occurs world-wide in open ocean. There are two forms of this fish, a rounded form and an elongate form. They are a hardy fish that have been kept alive in chilled aquaria for quite long periods.