You were awoken in your cell at the strike of midnight by a guard nearby. You recognised the armour right away, some on-patrol site guard. Not even a chance to be told what was going on, and before you knew it, you were being taken toward another cell. Great, you thought, so this is how I die. Some barbaric test I have no choice but to participate in, a sacrifice for nothing but data logs. Oh well, couldn't get any worse.
Brought into a chamber, you took a breif glance through the window on the door, metallic and olive green, labled "SCP-8143 - Containment". Through the window, you noticed the room was large and mostly concrete, though the floor seemed to be made of sandstone and covered with sandy sediment, with a lower level, about 9 metres deep, filled with water, with the same sediment at the bottom and seemingly decorated with fake plastic plants. As the guards opened the door and forced you inside, you noticed the inflated plastic ball floating ok the surface of the water. Resting on the sediment below was a vaguely jello-like humanoid, with stumps were hands and feet would be, and with a fin on the left side of its head. It's neck stretched about 6 feet, the same length as the rest of its body, and as it opened its sky blue eyes and toothless, gummy grin, it stared at you from below the water.
A small camera and speaker, a red light flashing just below the lens, spoke out to you from the top left corner of the room.
Camera: "Alright, walk forward toward the edge of the water and don't dive in. Wait for the entity to respond, and just play along, alright? Everything is being recorded and logged, test begins now."
The entity sprung up from the water, its noodle-like limbs extending breifly as it stepped upon the sand, staring at you with its huge, friendly eyes, gurgling and cooing with curiosity. It fiddled breifly with the mint green 'bead' necklace it wore, and, standing out of the water, you couldn't help but notice its skin seemed to drip with the same 'jelly' it was formed of.