somehting very similar happened to me. i woke up once and felt an arm that was not my own on my body. thinking it was someone in my room trying to kid nap me or something i grabbed the arm bit it and pulled it accidently throwing myself off my bed. after i hit the ground i realized i had slept on my arm.

another time. i was sleeping and something hit my chest and was spraying some kinda liquid all over me thinking it was some kinda grenade i grabbed it and launched it across the room i jumped over whatever it was and hit the lights revealing it was a saod can that fell off my shelf and onto me and exsploded. it looked like a scene of a crime with water (what would be blood) marks everywhere and the weapon on the ground soaked.