Basilisk

The Basilisk is nicknamed the "king of snakes." Described as being similar to a snake but with the head features of a rooster, simply because of its colourful crown, that sometimes may appear like a comb or a white diadem. Anyone who looks at it, meaning, has direct eye contact with it, will die instantly. It was created from the blood of Medusa. Other sources say the basilisk was hatched from the egg of a cockatrice, a type of dragon. 

There's many different accounts of the basilisk, although the earliest mention was from 79 AD book Natural History by Pliny the Elder. There the basilisk was described as originating from Cyrene, being only twelve fingers long, whose own hiss frighten away other snakes. According to Pliny, the basilisk's is fire breathing, as it destroys shrubbery and burns grass that it breaths upon. Only the rue plant is immune to the basilisk. It's able to destroy stones by it's incredibly noxious touch. It's believed that if a man on horseback should try and slay it with a spear, the venom of the basilisk would crawl up the spear and infect both man and his mount.

However the basilisk isn't invincible. One of the biggest threats to a basilisk is a weasel. The very odour of a weasel can kill a basilisk. Unfortunately the weasel would also be killed by the poisonous basilisk. Another danger to the basilisk is water. It panics at the sight of water mainly because it's from the sands of a desert. The creature is also afraid of its own reflection! Another interesting thing that can kill a basilisk is the cawing of a rooster. 

More info here: https://en.wikipedia.org/wiki/Basilisk

She Wolf Night