For me it's been waking up from bad dreams, fears, &c.

• Once instance of startled awake from a random noise to the image of a giant spider dropping onto me from the ceiling. Forget getting back to sleep simply from the adrenaline rush.

• Similar for waking up and breaking a nearby floor-standing lamp. Not a spider this time, but an amalgamation of horror-movie monsters out to get me. This instance I forget quite which ones were morphed together to eat//kill//torture me, but hell I jumped out punching and slashing much to the unfortunate fate of the albeit repairable lamp.

• Clinging to the side of my bed in utter fear due to what I can -- only in hindsight -- describe as "childhood night terrors". Utter black, silent, cold, empty darkness all around ... no walls or pillows or blankets for reference of where in my the bed I was despite whatever edge of my bed I was touching [I had a history of twisting and turning a lot, more on this later] ... no clocks either visible or ticking for what time it was so I potentially had ALL NIGHT shivering in cold and fear like this ... occasional fear of "monsters under the bed" healthily fuelled by my lifelong love of horror movies ... yea, great times. Barring experiences as a child solder or likewise victim, not recommended.

• Waking up mummified in my blankets. I'm serious. This is the "twisting and turning" I mentioned earlier. I had to be humiliatingly helped out of my sheets a few times because I had twisted myself up so tightly around and around and around, literally as some person's future actions had insulted my lifeline so much that my childhood self had to turn in his//my bed prior to turning in my//his grave. Not so much an issue these days, but heck.