An inkie is a sub-species of gloople. Like stickies, an inkie's main purpose is to break it's thin outer membrane by hitting a target. However, the outcome of this action is different. Unlike stickies, inkies are composed of a substance very similar to petrol. The area of the "inkie splat" is extremely slick, and will cause most invaders to slip and slide around long enough for a predator gloople to come and finish it off.
Also, while all glooples are flammable because of their alcohol based liquid insides, the inkie is especially so, and their ink, if ignited, will burn for a long period of time, or if compressed it may blow up!