They were blind by nature, relying on their sense of hearing to detect prey. Though not among their original prey, they were more than willing to kill and devour Humans.
Curiously, they were known for digging small tunnels, being able to easily carve through concrete and rock. However, after digging these tunnels, if they found larger areas, they preferred to avoid these tunnels at all cost, even letting prey hide within.
Due to the nature of the Vanish Sewers, the Molemen found themselves trapped within, unable to escape from the constantly shifting tunnels, that would often distort and destroy their own.
Markiplier developed a heavy hatred for the species, after having taken so long to escape the sewers.