What is manisium?

It seems there may be a typo in your question. If you meant "magnesium," it is a chemical element with the symbol Mg and atomic number 12. Magnesium is a lightweight, silvery-white metal that is essential for many biological processes, including muscle function and energy production. It is also used in various industrial applications, including the production of alloys and fireworks. If you meant something else by "manisium," please clarify!