Slime Cube

Slime cubes are sentient gelatinous lifeforms common in dungeons and caves. They can create armlike appendages to manipulate objects and use weapons. Slime cubes are also capable of engulfing their opponents and becoming formless.

Traits

Ability Score Increase. Your Constitution score increases by 2, and your Strength score increases by 1.

Age. Slime cubes can live for hundreds of years before gaining sentience. They are seemingly ageless, though their sentience might dissipate after several decades only to return decades later. They might have no memories from their previous periods of sentience.

Alignment. Slime cubes are still trying to understand what good and evil mean. Most are neutral.

Rarity. Legendary.

Size. You are 5 feet tall, 5 feet long, and 5 feet wide. You weigh around 300 pounds. Your size is Medium.

Speed. Your base walking speed is 25 feet.

Blindsight. You can perceive your surroundings without relying on sight in a 60-foot radius.

Armor Integration. With 8 hours of work, your armor can be integrated into your body, so you can’t take it off without 4 hours of work. Integrated heavy armor doesn’t reduce your speed, and it imposes no disadvantage on Dexterity (Stealth) checks.

Engulf. You move up to your speed. While doing so, you can enter Medium or smaller creature’s space. Whenever you enter a creature’s space, you attempt to grapple the creature. If you succeed, you enter the creature’s space, and the creature takes ld4 acid damage and is engulfed. An engulfed creature is considered grappled. The engulfed creature can’t breathe, is restrained, and takes ld4 acid damage at the start of each of your turns. When you move, the engulfed creature moves with you. If you fail, the creature can choose to be pushed 5 feet back or to the side of you. A creature that chooses not to be pushed suffers the consequences of a failed saving throw. An engulfed creature can try to escape by escaping the grapple. If the creature escapes and enters a space of its choice within 5 feet of you. While you have a creature engulfed, you have disadvantage on your attack rolls and Dexterity saving throws. You can cease engulfing the target at any time, releasing the engulfed creature in a space of your choice within 5 feet of you.

Formless Ooze. Using your action, you can discorporate into liquid ooze, causing everything you’re wearing and carrying to transform with you. This form lasts while you focus on it, as if you are concentrating on a spell. You can enter and occupy the space of another creature. Other creatures can enter and occupy your space. You can move through any opening that liquid can flow through. In this form, you can’t manipulate objects, attack, or cast spells, and objects that transformed with you can’t be interacted with. You can use this ability again only after you finish a long rest.

Gelatin Cube (Ooze). Your creature type is ooze. However, spells and effects that normally target only humanoids still affect you.

• You can extend two armlike appendages made of ooze to use for touching or holding. You can speak as though you had a mouth. Your voice emanates from you equally in all directions.
• You take up your entire space. Other creatures can enter the space, but a creature that does so is subjected to your Engulf trait and has disadvantage on the saving throw. Creatures inside you can be seen but have total cover. A creature within 5 feet of you can take an action to pull a creature or object out of you. Doing so requires a successful Strength check, and the creature making the attempt takes ld4 acid damage.
• You are vulnerable to cold damage. However, you can add your proficiency bonus to any saving throw against cold damage. If you have proficiency in such a saving throw, your proficiency bonus with it is doubled against cold damage.

Ooze Movement. Your fluid nature allows you to reduce the cost of moving through difficult terrain by 1 foot per foot you move. When you crawl, you can do so at full speed.

Pseudopod. Your unarmed strikes deal ld4 acid damage. Your unarmed strikes have the light and finesse weapon properties, and you have proficiency with them.

Languages. You speak, read, and write Common and Deep Common.