Wallomites are tiny creatures who feed on the energy of all other life. They thrive in shadows, blending seamlessly with their surroundings - providing they are not in direct light - where their edges can be seen. They must remain very still in sunlight or they will be noticed. They mostly made of energy, and not from this world. They have figured out how to invade our space by creating temporary "bodies" out of their membranes to manifest themselves. Many have become comfortable in these "bodies" and may not be able to return to whence they came. While they can still shape shift to a degree, the membranes become more fixed and rigid in this world.
They are mostly membrane, containing energy. Are evolving the ability to "grab" surfaces in this world. The membrane can change shape at any time.
Genetics and Reproduction
When full of energy, they are able to create a second membrane, which then splits from the first. There are no sexes, each one is able to reproduce by itself given enough energy source.
Growth Rate & Stages
They don't grow much, with age the ability to store and process energy diminishes until they feed off the energy of their own membrane. It shrinks and shrinks until it can no longer sustain the life force, the being dies, and only a piece of dust is left behind.
Ecology and Habitats
On the plain where these creatures mostly exist, they are the only living entities. It's them, and energy. They float around collecting different kinds of energy, using it to move around, they reproduce and die. Those who have come through into a physical realm have developed stronger membranes which can mimic shapes and grab onto surfaces.
Dietary Needs and Habits
All of their functions are supported by energy, which they draw through the membrane. The energy can come from movement, growth, sounds, the systems of other beings.
Wallomites are not affected by temperature or elements. They can live as easily in ice as they can in intense heat, provided there is enough energy to allow them to feed it into the membrane. They can withstand fire by using it's energy, but not for extended periods of time as the membrane can only hold for so long without rest.
Perception and Sensory Capabilities
They sense light vs. dark, movement vs. stillness. Can gauge distance only by the extension of perceived movement around them, up to about 10 feet. Their main ability is sensing energy sources.