The k'karee is a type of animal lifeform, a distinct species of poisonous snake native to the planet Vulcan. It is only one of dozens of species of poisonous snakes which inhabit the deserts of the Vulcan civilization's homeworld. Its appearance, namely its mottled blue-gray skin, is one of the factors that allows individuals to distinguish this species from the other snakes.
When the k'karee coils to strike, two sacs located below its throat expand outward, creating the appearance of a small pair of silvery fins and giving it the ability to project its venom in a concentrated spray with an effective range of up to 5 meters. The k'karee poison is not in itself fatal to humans or Vulcans, but it can temporarily paralyze a limb (for 24-48 hours) or cause blindness if it hits its target in the eyes. Either can leave a victim an inviting target to further attacks by the snake or by other predators in the area, unless proper antitoxins can be promptly applied. (Last Unicorn RPG module: The Way of Kolinahr: The Vulcans)