You know how to speak telepathically it can be used to communicate with any one you can see within 60 feet as long as they understand a language they can understand what you are saying.

You are a monstrosity.

You are medium.

Your walking speed is 30 ft.

You have darkvision up to 60 feet.

You have resistance to piercing damage. You also have advantage on saving throws to resist grapple, prone, and charm effects.

your many brains glow brightly as a bonus action to fill a circular radius of 5 to 15 feet with bright light and an additional 10 feet of dim light that lasts one hour or until the user chooses to stop producing light. Can be used up to 3 times and refreshes on a short rest.

you may use an action to cast comprehend languages and detect thoughts you may cast these an amount of times equal to your intelligence modifier per day, uses reset after a long rest. When you are in combat and you fall below half hp you lose this ability until you heal above half hp or until you leave combat.

You may move through any space big enough for a small rat to pass through and may move through spaces of enemies your size and above without issue.

Because you are composed of many different creatures you have advantage saving throws to prevent any effect that would sense your emotions or try to read your mind, others also have disadvantage to scry your location.

As you are composed of a swarm of cranium rats the more damage you take the more die and as your numbers lower so does your intelligence but become more coordinated due to less random rats getting in your way. When below half hp you have a -2 to intelligence and a +2 to dexterity.