This is me at least once a week. Wake up in the morning and wonder where the heck that came from. I always end up getting some mark on me some place. This one is the size of my fist and is on my leg. Most of the time they are on my leg. I always have no idea where they came from.
One day I woke up and had a dinner plate sized one on my tummy off to the left side. Now how the hell does this happen in my sleep. I can see a small one popping up now and then, but you would thing something 6 inches across would wake you up... NOPE.
I don't bruise easy normally, so I don't know where it comes from.
Then again I have the tenancy to not notice pain until it gets to a certain level. So you know... I could have damaged myself a bit and not noticed...