Your Constitution score increases by 2, and one other ability score of your choice increases by 1.

Slimefolk don't have a physical maturity per say and by other creatures standards, they are born physically matured. However, a slimefolk will take at three years to reach mental maturity beyond that of the standard behavior most oozes exhibit. As far as lifespan goes, slimefolk are not known to have one. Given their absence of recording their history and other races disinterest in them it makes it hard to say how long a slime folk will or can live, their bodies not showing any signs of age or decay. For reference sake, the oldest known slimefolk lived to be as old as an elves before perishing at about 700 years old.

Slimefolk, despite some saying they naturally bend towards chaos and evil, tend towards no particular alignment. Rather, they adjust to the alignment of the society they are in. When they do form groups with other slimefolk, they tend towards the lawful neutral alignment, however, this is more of a structure for social cohesion more than a tenancy towards following rules.

Slimefolk vary in size, and even individual slimefolk can change their size by taking in or expelling water from their bodies, but in general, slimefolk are comparable in size to most other intelligent races. Your size is Medium.

Your base walking speed is 30 feet.

You can speak, read, and write Common and Ooze, a dialect of Primordial. Ooze to those that speak Primordial sounds like a butchered version of Terran and Aquan. To everyone else, it is a bubbling, slushing language that sounds more like boiling mud then it does a language.

Your creature type is both humanoid and ooze. You don't require sleep and by moving across surfaces you can break down otherwise inedible substances to garner nutritional value.

You are composed of a large amount of liquid and as such, you fare poorly in the burning environments. You have disadvantage on saving throws against Extreme Heat.

For slimefolk, water is both an essential part of life and a death sentence. If you start your turn in a body of water, such as a lake, an ocean, or even outdoors in the rain, you take 1 necrotic damage at the start of each of your turns, the damage doubles for each cumulative turn you take damage from this trait. If your hit points are less then half of your hit point maximum when you take damage from this trait your speed is halved and you are considered to be poisoned until your hit points are restored to over half your hit point maximum. Finally, if you are reduced to 0 hit points by this trait you die.

Slimefolk learn to control their body by concentrating deeply. After a round of concentration, the Slimefolk can change its appearance into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. They can copy the appearance of armor and clothing as well as physical traits like hair, wings and tails though the effects are only cosmetic. While the slimefolk is disguised and not in their natural form, their ooze abilities are limited. The slimefolk can use a bonus action to revert back to its natural ooze form.

Additionally, you may take one hour to inspect a humanoid (or humanoid monstrosity), copying their movements and body shape, including sex. If you lose your concentration during this period, the transformation fails. At the end of the hour, you look almost identical to that humanoid, gaining any physical benefits, like the tail of a Yuan-Ti. You can only shape yourself like a humanoid or monstrosity that is humanoid in appearance. You keep this form until dispelled, after which you’ll need to re-investigate a being of that race for another hour to regain the effect again. You gain advantage to your Charisma (Deception) skill at any attempts to see through your transformation.

Slimefolk are known for the various forms that they can take, appears to be tall and lean one day, and then the next, being short and curvy. Their skin could be repelling arrows one day but get pierced by them by the next. At the end of a long rest, you can change simple miscellaneous details about your ooze form such as your "hair's" length or shape, make yourself a bit taller, smaller, wider or thinner. In addition, at the end of a long rest, you can also gain a resistance of your choice from, non-magical bludgeoning, piercing, or slashing damage. This resistance lasts until you pick another damage type with this trait.

While not using a weapon with the heavy property, your reach is doubled to 10 feet. In addition, when reaching vertically, such as to grab a ledge, you can add twice your height, instead of half your height.

Slimefolk, being creatures of gelatinous slime you are naturally sticky. You have advantage on Strength (Athletics) checks made to grapple a target. In addition, you can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. Additionally, creatures have disadvantage against trying to knock you prone or disarming you.

Your body leaks acid, creatures grappled by you take 1d4 on the start of your turn. Creatures attacking you with a touch or melee attack also take 1d4 damage. This ability works with the Stronger Corrosion mutation. You have advantage on saving throws against acid and are resistant to acid damage as well as able to use your action to eat through 2 inches of nonmagical metal or organic material, such as wood that is not worn or carried.

Due to the fluid nature of your form, you can move through a space as narrow as 1 inch without squeezing. You leave behind any items you are carrying, and any equipment which you are proficient with merges into your form until you exit the space.

Accustomed to gloomy caverns and fungi lit caves. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

Unless you are unconscious or dead (0 hit points), when moving on fertile soil or organic-rich environments, you regain hit points equal to 1/4 of your level rounded down every round.

Starting at 10th level, the damage die of your corrosive attacks and abilities increases by 1 size. A d4 becomes a d6. A d6 becomes a d8 and so on.

If you haven't moved on your turn when you attempt to hide, your coloration dissolves and you become transparent until you move, make an attack, fall prone, or cast a spell with a somatic component, either voluntarily or because of some external effect. While transparent, you can attempt to hide even when only lightly obscured or even in plain sight. While lightly or heavily obscured, Wisdom (Perception) checks made to see you have disadvantage and you have advantage on Dexterity (Stealth) checks. When you attempt to hide in plain sight, anything you are wearing or carrying that you haven't merged with may cause disadvantage on the Dexterity (Stealth) check or even completely prevent you from being able to do so.

A slimefolk is naturally corrosive, as such, your unarmed strikes may deal acid damage equal to 1d4 + your Constitution modifier, instead of the bludgeoning damage normal for an unarmed strike. Additionally, if your unarmed attack hits, you may use your bonus action to grapple the creature.

You may lose 5 hit points to make a ranged attack (range 20/60), slinging a part of your body on the ground. This goo quickly spreads to cover a 5ft area. Every creature starting or ending its turn in the goo needs to make a Strength (Athletics) or Dexterity (Acrobatics) check against your spell save DC or be restrained in addition they take 1d4 acid damage on the start of each of their turns. They may redo this saving throw every turn, ending the condition on a success.

Make a ranged attack (range 60) to choose one creature, or choose two creatures that are within 5 feet of each other, within range. A target must succeed on a Dexterity save or take 1d6 acid damage. Damage increases by 1d6 when you reach 5th, 11th, and 17th level.

You focus the acid into your hands to expel it into a 10 foot cone. The targets must pass a Dexterity save or take 1d12 acid damage, half on success. Damage increases by 1d12 when you reach 5th, 11th, and 17th level.

You may concentrate the acid that seeps from your body to make a ranged attack (range 90) in the form of an arrow. On hit, the target takes 4d4 acid damage immediately and 2d4 acid damage at the end of its next turn. On miss, the arrow does half the initial damage and no extra damage.

You control the acid that seeps from your hands, upon touching a weapon you coat it in a layer of acid that deals an extra 1d6 damage for an hour.

You concentrate to control the viscosity of the ooze in your body and thicken it to an almost solid consistency and gain resistance to non-magical bludgeoning, piercing, and slashing damage for one hour.