Your Constitution score increases by 2, while another score of your choice increases by 1. Due to the lab setting of their creation however, this is most commonly intelligence.

It is unclear how long gelatinous humanoids can last, though when created as infants  they take about 15 years to mature, and age very slowly if at all from there on out.
Their life span seems to depend on the skill of their creator, the type of ooze they originate from, and how often they take ooze form, life spans ranging wildly from 50 to over 200 years before the forces keeping their body together deteriorate and they return to the barely conscious ooze they were created from

Because of variation in creation, gelatinous humanoids can range anywhere from around 4 to above 7 feet, though most are very similar in size and proportion to humans. Your size is Medium.

Your base walking speed is 30 feet, and do to your affinity with none solid matter, you also have a swimming speed of 20 feet.

You can breathe air and water.

As an action you can allow your organs and bones to dissolve into ooze and abandon your humanoid form, melting instead into an amorphous ooze that can fit through cracks and keyholes and swim through the water. 

You’re under the following effects while in this form:

Liquid Movement. You have a walking speed of 10 feet in this form, but a swimming speed of 30 feet. You can move over or through other liquids. You can enter and occupy the space of another creature. You can rise up to your normal height, and you can pass through even Tiny openings. You extinguish nonmagical flames in any space you enter.

Amorphous Resilience. You have resistance to nonmagical damage.

Limitations. You can’t talk, attack, cast spells, or activate magic items. Any objects you were carrying or wearing meld into your new form and are inaccessible, though you continue to be affected by anything you’re wearing, such as armor. Your acidic touch does still affect objects and creatures that you come in contact with.

Your skin is acidic to the touch, though you can draw this acid back from the surface to allow you to interact with the world normally, or to cause a slight, damage-less tingling. at full force this allows you to do 1d4 aditional acid damage on unarmed attacked when your skin is exposed. In addition, you can push one tiny or smaller object into your body and have it dissolve over a series of hours. If this object is a creature it can make a dc 14 dexterity save to escape this fate. 
If the object consumed has any nutritional value, it acts the same as having eaten and digested that object. (good way to deal with chicken bones)

Used to stewing in your own acid, you have resistance to acid damage.

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