SCP-2019 a.k.a., The Gelatinous Brain Cube is a 5m x 5m x 5m sapient cubical organism composed of a green gelatinous substance held in place by a thick transparent membrane. SCP-2019's membrane is highly resistant to most forms of damage, and any parts that are removed from it grow back in a matter of seconds. On the lateral faces of SCP-2019 are 37 eyes. SCP-2019 is capable of moving these eyes around its membrane to see in all directions simultaneously. SCP-2019 is also capable of creating multiple tentacular appendages to allow mobility.
The interior of SCP-2019 grows brains at a rate that depends on available nutrients. At current feeding levels, SCP-2019 grows one brain every two months. When awake, SCP-2019 displays the ability to cause physical objects and living beings to manifest. It is only capable of creating objects and living beings within its line of sight, and all these creations disappear once SCP-2019 can no longer perceive them.
The Gelatinous Brain Cube cannot speak, but can communicate through visual conjurations. In an interview, the Gelatinous Brain Cube explained that it was banished from the rest of its kind due to being different somehow. After, the interview it is shown to fall in love with its interviewer and expresses the desire to turn others into copies of itself so it does not have to be alone anymore.