Kantrofarri

The dream crabs, properly known as the Kantrofarri, were predatory creatures that fed on humanoid brain matter. A crab would ambush its prey from above, wrapping itself around the person's face and pacify them by placing them within a telepathically induced dream state. The crab then drilled into the victim's right temple and slowly liquefied the contents within for consumption.

Victims trapped by a dream crab could fight against the crab if they realised that they were dreaming. In turn, the crab could further attack the victim within the dream and place them within multiple layers of dreams to make escape more difficult. If a person were to successful wake up from the dream, the crab would die and crumble to ash. Multiple people attacked by dream crabs simultaneously were able to share a common dream and interact with each other (TV: Last Christmas)