My imaginary creature is a puff of smoke born from the magma. Though magma is closely related to death, the smoke is something alive in that habitat. It's quite moody, sometimes responsive, sometimes avoidant. Appearance-wise, it consists of many particles. In the most original state, it's close to a sphere, with strong density in the middle and loose density on the edge. Those particles are flowing and moving slowly all the time.
It mainly has three stages of motion. First, when it's just wandering around, the particles spread out all over the place and just flow in the air, still having a center with higher density but the overall density of the whole creature is relatively low; Second, when a human force (represented by the mouse) tries to approach it, it avoids the human touch, so the space around the mouse will be empty; Third, the habitat it lives in which is the magma makes some sounds occasionally, which come with certain volumes and frequencies. The volumes control the density of the smoke while the frequency controls the position. The louder, the more dense and the higher frequency the higher position.