My best advice is don't take a painkiller until afterwards, and don't drink any alcohol for a good twelve hours before, at least. Just in case.
And, uh, yeah, not the same kind of shadows at all. The ones I'm talking about are... Okay, they're extra-dimensional beings, they live in a dimension that overlaps and surrounds our own, they have a fairly symbiotic relationship with humans because they feed off of all the things we generate, electric and emotional impulses, heat, everything, and if we didn't have them around to do it, we'd probably go crazy from the excess.