Board Thread:General Discussion/@comment-32455678-20170702063923/@comment-27136653-20170805203520

Perhaps you mean bone marrow. That stuff is red, but only because it contains blood. Normally it's yellow. But still, that stuff isn't runny enough to drip all over Sans like that. And bones contain holes for capillaries. All blood in him should naturally flow out through those holes, provided it doesn't clot. In which case, it shouldn't be able to flow at all, so it shouldn't leak all over him like that.