Guianan Cock-of-the-rock, Rupicola rupicola

The only animal on this list that gets a mention for being pretty, the Guianan Cock-of-the-rock is notable for the male's bright orange plumage and dramatic half-moon shaped head crest, which sometimes totally obscures its beak and lends it an odd appearance.

 

Blobfish

The blobfish (Psychrolutes marcidus) is a fish that inhabits the deep waters off the coasts of Australia and Tasmania. Due to the inaccessibility of its habitat, it is rarely seen by humans.
Blobfish are found at depths where the pressure is several dozens of times higher than at sea level, which would likely make gas bladders inefficient. To remain buoyant, the flesh of the blobfish is primarily a gelatinous mass with a density slightly less than water; this allows the fish to float above the sea floor without expending energy on swimming. The relative lack of muscle is not a disadvantage as it primarily swallows edible matter that floats by in front it

Dumbo Octopus

The octopuses of the genus Grimpoteuthis are sometimes nicknamed "Dumbo octopuses" from the ear-like fins protruding from the top of their "heads" (actually bodies), resembling the ears of Walt Disney's flying elephant. They are benthic creatures, living at extreme depths, and are some of the rarest of the Octopoda species.

Tarsier

Tarsiers are prosimian primates of the genus Tarsius, a monotypic genus in the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. The phylogenetic position of extant tarsiers within the order Primates has been debated for much of the past century, and tarsiers have alternately been classified with strepsirrhine primates in the suborder Prosimii, or as the sister group to the simians (=Anthropoidea) in the infraorder Haplorrhini. Analysis of SINE insertions, a type of macromutation to the DNA, is argued to offer very persuasive evidence for the monophyly of Haplorrhini, where other lines of evidence, such as DNA sequence data, had remained ambiguous. Thus, some systematists argue that the debate is conclusively settled in favor of a monophyletic Haplorrhini.
Tarsiers have enormous eyes and long feet. Their feet have extremely elongated tarsus bones, which is how they got their name. They are primarily insectivorous, and catch insects by jumping at them. They are also known to prey on birds and snakes. As they jump from tree to tree, tarsiers can catch even birds in motion.[citation needed] Gestation takes about six months, and tarsiers give birth to single offspring. All tarsier species are nocturnal in their habits, but like many nocturnal organisms some individuals may show more or less activity during the daytime. Unlike many nocturnal animals, however, tarsiers lack a light-reflecting area (tapetum lucidum) of the eye. They also have a fovea, atypical for nocturnal animals

Aye-aye (ugliest animal I have ever seen)

The Aye-aye (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.
Daubentonia is the only genus in the family Daubentoniidae and infraorder Chiromyiformes. The Aye-aye is the only extant member of the genus (although it is currently an endangered species); a second species (Daubentonia robusta) was exterminated over the last few centuries.

Axolotl

The Axolotl (or ajolote) (Ambystoma mexicanum) is the best-known of the Mexican neotenic mole salamanders belonging to the Tiger Salamander complex. Larvae of this species fail to undergo metamorphosis, so the adults remain aquatic and gilled. The species originates from the lake underlying Mexico City. Axolotls are used extensively in scientific research due to their ability to regenerate most body parts, ease of breeding, and large embryos. They are commonly kept as pets in the United States, Great Britain, Australia, Japan (where they are sold under the name Wooper Rooper, and other countries.
Axolotls should not be confused with waterdogs, the larval stage of the closely related Tiger Salamanders (Ambystoma tigrinum and Ambystoma mavortium), which is widespread in much of North America which also occasionally become neotenic, nor with mudpuppies (Necturus spp.), fully aquatic salamanders which are unrelated to the axolotl but which bear a superficial resemblance.