All* of the below is being created by Slycotton.

Credit to the Trebhum and their original game The Eternal Cylinder goes to ACE Team

Version X

Trebhum

Trebhum are not the strongest, nor the fastest, and they do not have large teeth. But Trebhum are loyal, resourceful, and very, very stubborn.

Traits

You have proficiency in the Survival and History skills.

Creature Type: You are a Beast.

Speed: Your walking speed is 25 Feet. While moving at a fast pace, you are rolling like a ball on the ground.

Size: You are Small.

Ability Score Increase: Increase your Dexterity by 1, and your Constitution by 2.
Natural Armor: You have +2 to your AC.

Genetic Memory: Trebhum can share information about creatures, locations, objects etc. with all other Trebhum across generations, as well as with other live Trebhum. This functions almost like a hivemind with other Trebhum.

Offenseless: Trebhum cannot make unarmed strikes.

Trunk: Trebhum have no arms, and instead use their dexterous trunks to manipulate and hold objects. This limits them to only one "arm" and thus cannot hold two objects at the same time. This trunk can also spew out water in a stream, though not very effectively.

Body Storage: Trebhum store objects inside their bodies and suck up objects into their bodies via their trunk, and retrieve these items by spewing them out from the same trunk.

Bodily Limitations: Trebhum cannot wear regular clothing besides hats or shoes. Trebhum cannot wear any storage bags or containers. Trebhum cannot wear armor.

Languages: Your character can speak, read, and write Common, Trebhish and one other language that you and your DM agree is appropriate for the character.

Mutations

Trebhum can consume specific materials or foods to mutate their bodies. The DM will decide if a certain food or edible material will give a Trebhum any of the below mutations. A Trebhum may only have one of each mutation type at a time. (Legs, Trunk, Body, Skin, and Eyes.) Getting a new mutation of a type you already have mutated will replace the part you already had with the new one unless stated otherwise. When creating your character, you may choose to have up to two of any mutations marked as a Starter mutation. The rarity markings on the mutations will assist a DM on when to allow a Trebhum to access an item that gives that mutation. 

Leaping Legs

Legs - Starter - Common

Trebhum with this mutation gain +4 feet to their jump height.

Webbed Feet

Legs - Common

Trebhum with this mutation gain a swim speed of 35.

Quadruped Legs

Legs - Uncommon

Trebhum with this mutation gain +10 to their walking speed.

Sucker Legs

Legs - Uncommon

Trebhum with this mutation gain the ability to, as an action, stick themselves to any surface. This sets their speed to 0, and prevents them from benefitting from any bonus to their speed. This disables them from being moved by any force until they stop sticking. A Trebhum can unstick whenever they want as a bonus action, but they may only stay stuck for up to 3 turns.

Stealth Legs

Legs - Rare

Trebhum with this mutation create no sound via walking, giving them advantage on all sound-dependent Stealth checks unless otherwise given disadvantage.

Deimatic Trunk

Trunk - Starter - Common

Trebhum with this mutation gain the ability to, when making Intimidation checks, make a loud tuba-adjacent noise with their trunks that adds +2 to the result. This ability has a cooldown of 15 minutes.

Filter Trunk

Trunk - Starter - Common

Trebhum with this mutation gain immunity to any Inhaled poison.

Hose Trunk

Trunk - Starter - Uncommon

Trebhum with this mutation can spray water from their trunks much more accurately and quickly than without the mutation.

Hypnotic Trunk

Trunk - Common

Trebhum with this mutation know the Charm Monster spell. The knowledge of the spell is removed if the Trebhum loses this mutation, but if the Trebhum knew the spell previously without the assistance of the mutation, the spell stays.

Tongued Trunk

Trunk - Rare

Trebhum with this mutation gain the ability to make unarmed strikes.

Pyrogenic Trunk

Trunk - Rare

Trebhum with this mutation know Fire Bolt, and the end of their trunk will passively generate a small flame. The flame at the end of the Trebhum's trunk does not effect items they add to their inventory via the Trunk.   The knowledge of the spell is removed if the Trebhum loses this mutation, but if the Trebhum knew the spell previously without the assistance of the mutation, the spell stays.

Fumogenic Trunk

Trunk - Uncommon

Trebhum with this mutation know Fog Cloud. The knowledge of the spell is removed if the Trebhum loses this mutation, but if the Trebhum knew the spell previously without the assistance of the mutation, the spell stays.

Storage Body

Body - Starter - Common

Trebhum with this mutation gain a bonus to their inventory carrying capacity equal to a backpack. Trebhum cannot remove this mutation by any means if their inventory currently carries more than their inventory capacity without the mutation.

Amphibian Body

Body - Common

Trebhum with this mutation automatically succeed on any saving throw or check related to swimming.

Cuboid Body

Body - Rare

Trebhum with this mutation can fit through cube-shaped holes or doors that aren't smaller than them. 

Water Processor

Body - Common

Trebhum with this mutation automatically process organic foods or items into water. An item takes it's weight in pounds multiplied by 2 minutes to be converted. Once an item is converted, it cannot be un-processed. All organic items are affected by this unless the DM specifies otherwise. A Trebhum cannot control if this happens. This effect does not occur with items stored in containers the Trebhum is holding.

Plated Body

Body - Uncommon

Trebhum with this mutation gain +6 to their AC. 

Inflatable Body

Body - Rare

Trebhum with this mutation gain the ability to, as an action, inflate their bodies like a balloon. This allows them to slowly glide in the air, and be lifted up into the air by any air draft strong enough. While inflated, the Trebhum can move up to 5 feet horizontally for every 1 foot it descends in the air at no movement cost to it. When the Trebhum would take damage from a fall, the Trebhum can use it's reaction to reduce the fall’s damage to 0.

Regenerative Body

Body - Rare

Trebhum with this mutation constantly regenerate 2 HP every 15 minutes.

Mixer Body

Body - Uncommon

Trebhum with this mutation can mix items in their bodies to create bombs that range differently in power. 

Furred Skin

Skin - Starter - Common

Trebhum with this mutation automatically succeed on any saving throw related to environmental cold temperatures. This is not related to Cold damage.

Reptilian Skin

Skin - Uncommon

Trebhum with this mutation automatically succeed on any saving throw related to environmental hot temperatures. This is not related to Fire damage.

Crystalline Skin

Skin - Rare

Trebhum with this mutation gain +2 to their AC, and reflect light that hits them as bright light in a radius of 5 feet and dim light in a radius of 20 feet.

Electrogenic Skin

Skin - Uncommon

Trebhum with this mutation may shock any incapacitated creature to awake them and allow them to have turns. This ability has a cooldown of 2 days.

Aposematic Skin

Skin - Uncommon

If a Trebhum with this mutation is dealt melee Piercing, Bludgeoning or Slashing damage, it deals 1d4 Piercing Damage to the attacker.

Luminescent Skin

Skin - Rare

Trebhum with this mutation constantly shed bright light in a 20-foot radius and dim light for an additional 20 feet. Completely covering the Trebhum with something opaque blocks it's light.

Entomophilous Skin

Skin - Uncommon

Trebhum with this mutation attract all nearby flying insects to their location in a 70 foot radius. The effect is blocked by walls.

Iridescent Skin

Skin - Rare

Trebhum with this mutation are shiny, sparkly, and very attractive, as any Trebhum should be.

Luminescent Skin

Skin - Rare

Trebhum with this mutation constantly shed bright light in a 20-foot radius and dim light for an additional 20 feet. Completely covering the Trebhum with something opaque blocks it's light.

Analytical Eyes

Eyes - Uncommon

Trebhum with this mutation automatically roll an 18 on a history check for any creature, and any other Trebhum party members gain the same knowledge.

Extendable Eyes

Eyes - Common

Trebhum with this mutation have the ability to, as an action, extend their eyes up to 30 feet into the sky to have an aerial view of their surroundings. The Trebhum can have their eyes extended for as long as they like, but cannot commit other actions while extending their eyes.

Perceptive Eyes

Eyes - Uncommon

Trebhum with this mutation TBA

Ionic Vision

Eyes - Rare

Trebhum with this mutation have the ability to, as an action, possess any inanimate object unless otherwise stated by the DM. While possessing the object, the Trebhum's normal body is still exposed, and cannot take actions unless the Trebhum stops possessing the object. A Trebhum can possess the object for as many turns as they please. While possessing the object, the Trebhum can see through the eyes of the object, or where the eyes of the object would be if it had eyes. Trebhum cannot walk or take advantage of any powers the object may have, and can only move slightly to look around. Possessing the object counts as a turn, and thus the Trebhum can only take actions possessing the object after the first turn used to possess it. Stopping possession of the object counts as a bonus action.

Mutation Appearences