Friends or Enemies? (8)

Recently, I hadn't been having very many dreams, and if I was dreaming, they seemed to be pretty boring for the most part.  However, a few nights ago that all changed.  I had a dream that two of my friends basically tried to kill me (or so I thought).  In the context of the dream, my friends seemed like they were trying to play a prank on me by placing a black sackcloth type thing over my head, and then trying to put me into what looked like a body bag.  When this was taking place,  I was seeing all this happen from outside of my body like I was somebody else.  It wasn't until my friends started to put me in the body bag that I started to experience the dream from my own body.  Once that change occurred, I was panicking and begging my friends to stop and leave me alone, and finally they stopped and took the sackcloth off my face.  As soon as the cloth was removed and I could see, the dream was over.  Even though my friends' demeanor was a playful one throughout the dream, I clearly wasn't a fan of this prank!  Now that I understand nightmares are a way for our brain to attempt to prepare us for certain events in our lives, I wonder what the purpose of this dream was.  I didn't wake up extremely scared like most nightmares cause me to do, but I did feel weird that I thought my friends were going to kill me!