We could have an enemy that was invisible and under the undead catagory the way you would see it would be by its trails of footprints and dust being left behind? The way to fight it would be to put it in darkness and keep it there to have it sprout out of the ground and continue walking in a more vulnerable and viewable fassion. It would be neutral at first until provoked and would display a mean nasty attack that was hard to counter by swords but easy to counter by bombs or guns. It would be a more advanced with attacks if provoked more or weakened throwing projectiles (not just limited to orbs but also other items i.e bones or stones off the ground) dash attacks, teleporting nake- err i mean attacks and would have a mean detonation at death.
What Im thinking is it should have a name called the "Gate Keeper" because it would usually have a key on hand or something to weigh down a gate with a pressure plate. If more then one are found they would all need to be killed to provide bits of keys or weights.
In other news this could be a cool way to introduce battle weapons such as spears or scythes which even though are not exactly battle weapons can hold their own in battle form.
Now debate time let the war be great but the blood little because I am a bit squeamish if I do say so myself.
We do have a Ghostmane stalker.
They have a recons ability.