In the animal kingdom, looks can be deceiving. A seemingly hug-able creature with big brown eyes and fluffy fur could be a deadly killing machine in disguise. Most animals will do whatever is necessary to remain free, procreate, protect their young, keep their territory, and eat a belly full of something scrumptious. Here are 15 animals that you’ll probably want to run away from, no matter how adorable they look on those wall calendars.
15. Wolverine (Gulo gulo)

Source: (Link)
The wolverine is a stocky, thick furry and muscular animal. With short legs, broad and rounded head, and small eyes with short rounded ears, it resembles a cute little bear you would want to cuddle with.
Why deadly?
This is one weasel you don’t want to mess with. Its aggressive nature is widely known, thanks to the popularity of the X-Men comics and movies. Armed with powerful jaws, sharp claws and a thick hide, the wolverine has a reputation for ferocity and strength out of proportion to its size, with the documented ability to kill prey many times its size.
14. Australian Box Jellyfish

Source : (Link)
Box jellyfish most visibly differ from the “true” jellyfish in that their umbrellas are cubic, rather than domed or crown-shaped. Box jellyfish can not only move more rapidly than other jellyfish due to their slightly different structure but are also significantly more beautiful as they are almost transparent.
Why deadly?
You dive and see this magnificent beauty (or even if you don’t see) then don’t dare to touch it because the box jellyfish has been called “the world’s most venomous creature”, though only a few species in the class have been confirmed to be involved in human deaths. It is a sea wasp, the Australian box jellyfish can have up to sixty tentacles, each 15-foot long and with enough venom to kill 60 people.
13. Cassowary

Source: (Link)
A cassowary looks like a flamboyant ostrich and can be found wandering the rain forests of Australia and New Guinea. Young cassowaries are brown and have buffy stripes. They are often kept as pets in native villages [in New Guinea], where they are permitted to roam like barnyard fowl. Cassowaries feed mainly on fruits, though all species are truly omnivorous.
Why deadly?
It prefers to keep a low profile, but when disturbed this flightless bird can become extremely aggressive and territorial. Often they are kept as pet until they become nearly grown and someone gets hurt. Capable of running and leaping at high speeds, the cassowary attacks by thrusting its large claws forward with the aim of disemboweling its target.
12. Pfeffer’s flamboyant cuttlefish

Source: (Link)
It is a small beautiful 3.1 inch (8 centimeter) aquatic organism exhibiting radiant charm and velvety appearance. The dorsal surface of its cuttlebone is yellowish and evenly convex. The texture throughout is smooth, lacking bumps or pustules making it one of the most beautiful life forms in marine. It occurrs in tropical Indo-Pacific waters off northern Australia and southern New Guinea.
Why deadly?
Don’t try to cuddle this cuttlefish. Though charming and colorful, this aptly named fish’s displays are meant as a warning. Although they rarely encounter humans, its poison is considered extremely toxic and can be as lethal as the poison of the blue-ringed octopus.
11. Poison Dart Frog

Source: (Link)
Unlike most frogs, these species are active during the day and often exhibit brightly-colored bodies. Most of them are beautifuly radiant, displaying aposematic patterns. They are found in a multitude of colours making them the most beautiful frog specie.
Why deadly?
Their bright coloration is associated with their toxicity and levels of alkaloids. Poison dart frogs secrete lipophilic alkaloid toxins through their skin. Alkaloids in the skin glands of poison frogs serve as a chemical defence against predation. Although they won’t be deadly to you but might be deadly to your tiny house pets or if you drink the water they have swimmed in.
10. Siberian Chipmunks

Source: (Link)
The idea of a 50 gram cute, tiny and fluffy chipmunk with its adorable curly tail drinking from a baby bottle is enough to warm even the coldest hearts. Chipmunks are small squirrel-like rodents native to North America and Asia. The chipmunk stands about six inches from nose to tail, and has been known to burst suddenly into a harmonious melody if they hear the tickled ivories of a well tuned piano Well how adorable and sweet!
Why deadly?
Their aggression is although cute in a way that at most they will try to snatch a sandwich from you at a picnic. Then what exactly I’m talking about deadly is the possibility of harboring a disease. Siberian Chipmunks have been reported as spreading throughout many areas of the world, bringing with them, ticks (Lyme disease) and rabies. Although treatable, if the disease remains undetected and left untreated, heart and neurological problems can ensue, followed by coma and death.
9. The Swan

Source: (Link)
Such poise. Such grace. The way they glide effortlessly across the water. That unmistakable curve to their necks that forms a perfect heart when they nuzzle with their mate, who they will stay with for the rest of their lives. The epitome of grace and beauty, the swan is one of the last animals we’d imagine to be anything other than elegant. Tranquil ponds and romantic scenes wouldn’t be complete without a pair of white swans floating peacefully along.
Why deadly?
They are not only relatively gentle creatures in nature, but they are also terrific parents and would protect their young to the bitter end. And here lies the problem. Many birds have an instinct to protect their young when approached by a predator, but they will eventually give up if the predator is too strong or dangerous to deter. The swan however, does not give up. Not only do they attack by flying at perceived threats at full speed and biting them, they’ll also try to drown you if given the chance: They are known to fly up over and try to keep something underwater if they perceive it as threat. Getting chased through a park by a furious bird that will not stop trying to rip your skin off your bones is only funny until it happens to you. (Source)