Swarm of Cranium Rats

D&D 2024 monster: Swarm of Cranium Rats. Source: Mordenkainen Presents: Monsters of the Multiverse. challenge rating 5, creature type Aberration, Medium size... Cranium Rat Mind flayers create cranium rats by bombarding rats with psionic energy. Cranium rats are somewhat smarter than ordinary rats and behave as such. If enough cranium rats come together to form a swarm, they merge their minds into a single intelligence with the accumulated memories of all the swarm's constituents. The rats become smarter as a result, and retain their heightened intelligence for as long as the swarm persists. The swarm also awakens latent psionic abilities implanted within each cranium rat by its mind flayer creators, bestowing upon the swarm psionic powers. A single cranium rat uses its natural telepathy to communicate hunger, fear, and other base emotions. A swarm of cranium rats communicating telepathically "speaks" as one creature, often referring to itself using the collective pronouns "we" and "us." Some mind flayer colonies use cranium rats as spies. The rats invade communities and act as eyes and ears for the colony's elder brain, transmitting their thoughts when they swarm and are within range of the elder brain's telepathy. Aberration Medium 30 ft.