The Creation of Mounds
Before you know about mounds, you need to know about meteorites. There are two types of meteorites; primitive and differentiated. Primitive meteorites are meteorites whose composition of metals, minerals, and space dust has been unchanged since its formation. Differentiated meteorites have been altered by heat and pressure, therefore it's composition is processed and all melted together to make one consistent material.
The creation of mounds starts on a foreign planet, when an extraterrestrial creature accidentally stumbles and begins orbiting it's planet at a very low altitude. When this happens, small stones, rocks, and pebbles magically adhere to the creatures body and tumble around with the orbiting creature. This phenomenon creates a katamari, a magical adhesive ball where anything smaller than it sticks to its surface!
After a few orbits, the creature will become entirely contained in a ball of space matter and eventually launched out of its planet's orbit and into space! Sometimes, in our case, the katamari meteorite will get close enough to Earth that it collides into our surface and implants its self into the crust! Over time, the landing site becomes covered in dirt and foliage to create a mound.
This mound is the resting site of the fallen katamari meteorite and space creature. The pressure and heat from the Earth fuse the space matter together to form a differentiated shell around the hibernating creature, keeping it stable until the day it can emerge from it's shell and create a new life on Earth. Though this isn't the death of the space creature, these mounds are sometimes referred to as katamari burial grounds.