Muddy is a 12-chapter manga created by Shou Aimoto. It follows Clay, a former child prodigy who was hired to make chimeras, but is fired due to lack of results. He ends up at an abandoned facility, where he somehow creates a chimera human, which has never been done before. Clay names this being Muddy, and they go out into the world together.
Clay's Decision (Volume 1, Chapter 3)
Muddy pretends to be pregnant by eating a lot of soil and changing his mass.
Reunion (Volume 2, Chapter 11)
While at the beach for the first time, Muddy eats the earth there.