You’re bound to a pretty dapper hat (Your Charisma increases by 2). You’re also a old and menacing monster that reigned for a long time (Choose to increase Intelligence, Wisdom, or Charisma by +2).

Unless you are physically destroyed you will never die, your mind will never age, and you will remember everything.

You were originally sealed away for your evilness but it’s your choice whether you became a better person while in hatty isolation or hatred and rage had been brewing inside that piece of clothing for millenniums, waiting to burst out.

Your physical form is a literal hat, your size is Tiny.

Your base "walking" speed is 20 feet. In reality you hover up to 10 feet off the group, across no larger than 10 foot gaps, and are unable to jump. However should you be possessing someone, you can mount the tops of their heads and inherit their movement speed as well as where they move.

Although you’re really a monster, your physical form is a hat made of a variety of materials. Your creature type is Construct.

-Spells like cure wounds don't affect you as you are a construct and spells like crown of madnessor dominate person have no effect on you due to them specifically targeting humanoids.

-You are immune to poison damage, being poisoned and diseases.

-You do not need to eat, drink, or breathe.

-Instead of sleeping, you enter an inactive state for 4 hours each day. You do not dream in this state; you are fully aware of your surroundings and notice approaching enemies and other events as normal.

Your magical creation has left you with the ability to see in the dark up to 60 ft, and truesight up to 10 ft. You can’t discern color in darkness, only shades of gray.

Your small and irregular hat vessel makes it impossible to find armor that fits you unless it is specifically tailored to you. You cannot wear any form of armor or clothing unless it is specifically made and designed for you.

But even if you can’t wear armor and you have the innate fragility of a hat, you shouldn’t be underestimated. You use your sheer magical power to make built-in defensive layers on your hat. Whilst not wearing specialy made armor, your AC is 14 + your Charisma modifier.

You know Mage Hand as a cantrip.  This does not count against your known or prepared spells.

While you remain motionless on the ground or a surface, you’re indistinguishable from a normal hat.

You can’t escape your hatty fate but you can transfer your consciousness into another hat over the course of a short or long rest. During that time you or another creature performs an hour-long ritual. Over the course of that hour, you must remain within 5 feet of the desired hat or the ritual fails.

One Creature that you can see within 5 ft. you must succeed on a DC 18 Charisma saving throw or be possessed by you; the target is then Incapacitated and loses control of its body. You now control the body and deprive the target of awareness. You can't be targeted by any Attack, spell, or other effect. You retain your Alignment, Intelligence, Wisdom, Charisma, and immunity to being Charmed and Frightened. You otherwise use the possessed target's Statistics, but don’t gain access to the target's knowledge, Class Features, or Proficiencies.
The possession lasts until the body drops to 0 Hit Points, you end it as a Bonus Action, or you get forced off by target making a DC 20 Strength saving throw. When the possession ends, the target is immune to this Possession for 24 hours after succeeding on the saving throw or after the possession ends.

Once you have possessed someone, their conscious is put into a nightmare where they can see your true form. You can control the setting of the nightmare and what happens in it. You can directly attack the possessed targets conscious each round they’re possessed which always hits and deals 1d4 + Charisma modifier psychic damage. This attack increases to a d6 at 5th level, d8 at 10th level, d10 at 15th level, and d12 at 20th level.

Your a hat so you don’t have a mouth or vocal cords to communicate but you know the Message cantrip and can cast it at will without needing components.

You can speak, read, and write Common and 1 other language of your choice.