Is it normal that i laugh about people dying?

Okay, so I never used to do this, but recently, say the last 2 months, I've been dreaming/thinking about my friends, families and enemies dying from me, or just dying in general, and just smiling or laughing about it. Whenever I think about these things, they always die a painful and horrible death. Strangely enough, I never smile or laugh if I think about my dog dying. Can someone please tell me what this is? I also have been in domestic violence at a young age. And extreme arguments with my parent. Please explain to me what this is, and if This should be normal.