Survey: When you wake up in the morning do you find bruises or scratches on your body that you didn't have?

No, that's not a common occurence.

No, it's more mysterious. I think it takes a few days for the bruises to appear, and for the life of me, I cannot remember what I banged into or dropped on myself. 

No. There are several possibilities. You are being abducted by aliens and experimented on at night. You are on meth and it's causing scarring. You are a restless sleeper and hitting yourself. Or you had them already and forgot about the bruises.

Once my brother noticed he had a big scratch on his neck when woke up XD

I bet it was the cat

yes but im a restless sleeper and move around a lot plus i have cats that sleep with me.