I had a dream i was grim reaper?

I had this dream where I was entering like a subway station, but through a trap door. And it was really dark and foggy down there. There was no people there, except a few bodies. I wasn't afraid, i felt invincible. As I looked down upon myself I saw that i was wearing a black cloak and was holding a skythe. What does it mean to have a dream that you are the grim reaper? And also, towards the ending of the dream i picked up the phone and whispered something, and the voice from the phone answered "death, death" in a really fearsome voice and tone.