Octopider

You may be thinking, “A spider already has eight legs… Why Octopider?” For one thing, the Octopider is much larger than a spider, closer to the size of an octopus. It's legs, although they can scurry like a spider, are actually the tentacles of an octopus. In fact, this monstrosity has nearly all the most terrifying features of both spiders and octopi. The Octopider can move easily in water or on land. Whenever threatened, the Octopider disappears into an inky, venomous cloud. They say the Octopider was a grotesque creation of the Gorlodon, a famed monstrous dark sorcerer of the deep water.