I was wonderring about dark matter . Assuming it is there and has gravity but cannot be seen . Can it form a black hole that cannot be seen also ? And would it only suck in other dark matter even though it has an affect on local gravity at the very least ? Since we don't know exactly what dark matter is but we know it effects gravity (has mass) I can't help but wonder if it can create a dark star or maybe ever a dark black hole . With the concept of multiple dimensions and such I would also question if the dark matter just dosen't occupy our percievable dimension .