Basilisk

A large walking snake with a grounded lower body with fore and hind legs, and a long upraised upper body. The basilisk is the king of a snake den, and typically the largest in a family of snakes: the second largest being his queen as his closest equal. A basilisk has a piercing gaze that will shock and paralyze its victim, and ultimately petrify (turn to stone) after a prolonged glare. The venom of a basilisk is highly poisonous, and is an extremely corrosive acid. 
Basilisk venom is known as Icritus, used for poison weapons, or as a corrosive solvent. 
The queen snake is known to be very vicious and large, and certainly poisonous, yet lacks the many basilisk qualities of her mate (limbs and a piercing gaze, and corrosive venom).