My most terrifying dream was also the only case of sleep paralysis that I've ever experienced
It happened a couple months after my grandmother died. In the dream my family had gone over to her house like we always did every Sunday since I was little. My dad, grandpa and I were watching football in the living room when I go to the kitchen to get some water. The kitchen has a hallway that leads to the bedrooms and down this hallway I see my grandma. I remember feeling off put because I knew she was dead but I also felt comfortable like I always did when talking to her. So I go and chat with her and she's her normal self; she asked me about school and work and how I was doing.
Finally, I told her I missed her and went in for a hug when all of a sudden I felt this intense pain in my stomach. I looked down and I saw her fingers jabbing into my gut and I felt them curl up and grab the bottom of my ribcage from the inside. Unable to breathe I looked up at her and find that her eyes have sunk in and gone black, her skin is gray and her face begins to stretch and contort in a disturbing way that still bothers me when I think about it.
That's when I woke up paralyzed. It felt like there was a massive weight on my chest and an overwhelming sense of dread washed over me. Now I'm not a superstitious person and whenever I have a usual nightmare I'm able to fall back asleep no problem; but I can't describe this any other way than feeling my life intensely threatened. I even tried yelling for someone but I wasn't able to make any sounds. After the longest couple minutes of my life it just sort of wore off I guess and I sat up, flicked on the light and came to my senses so I was able to just go back to sleep. That particular nightmare will probably be burned into my memory forever thought.
TL;DR: Had dream about my dead grandma which lead to sleep paralysis. No bueno.