There is an entity known as M.exe that is seemingly immortal, as the only way to destroy it is by erasing the main code from Mephisto and freeing Mario's soul, a feat that has yet to be accomplished. M.exe wields a large knife as its preferred weapon. Additionally, M.exe has a psychological connection with its environment. If anyone enters its territory, much like Sonic.exe, M.exe will detect their presence without delay.