In appearance the creature resembles a small purple worm with tendrils from it's mouth. It is approximately 7 inches long, and at the "bottom" of it's mass, it becomes a purple blob, about 9 inches in both length and width, in a rough circular pattern. But despite it's small size the creature is horribly dangerous. It can expand it's mass to engulf and devour humans, and by doing so gains the ability to imitate their form and behavior. To make matters worse the creature isn't actually intelligent, it just does a very good job faking it. So it's truly impossible to reason with. With each person it eats it grows larger, and as it increases in size it becomes capable of infesting the building, controlling machinery it's connected to, and turning the walls into a fleshy mass. You can only hope to escape or kill it before things get that far.
(You can have as many characters as you want, but they are at risk of getting eaten. I'll be playing the Creature, and as many can join in as want to, no need to ask.)