Pliable Stalker

This one is another regular character of my nightmares, but fortunately, I haven't seen it much lately. 

It's really hard to fight or get away from. Its long arms are very flexible, can get longer and skinnier, bigger or smaller, and can re-shape themselves to fit into any little crevice or hole. If I lock a door, it just reaches into the keyhole and unlocks it. If I run, it stretches and runs faster than me. It will catch up with me, run beside me, and grin like mad.

"Hello. Would you like to stay for dinner?"

If I try to fight back by physical means, I find myself wrapped up in those arms, with the fingertips becoming more solid and digging into my ribs like knives while I'm bitten around the hands, face, neck, and shoulders. 

Sometimes, the glow that shows from inside of him made those bites burn like fire.Other times, there was no heat, but that glow lit up everything around him, so I couldn't use darkness to hide. Sometimes it was as though there was blood all over him.

If I'm having a borderline lucid dream, I can escape by flying away, though the arms stretch after me. There is a limit to the length it can achieve. 

Sometimes, I get to the point of lucid where I know I can defy the laws of physics, but still don't realize I'm dreaming (weird, I know but happens to me a lot) and I can use "magic" to kill it, but even with that lucidity, anything related to fire doesn't hurt it. Instead, I fly up in the air and shout "light," and a ball of light will shoot from my hands, grow as it goes, and engulf the thing in brightness until I can't see it. There is always this ragged Godzilla kind of scream from inside the light, and then it disappears, leaving behind scorch marks and blood.

I used to dream about this thing all the time, though less frequently now, with the setting often being some unfamiliar building. Not knowing the territory made it harder to run away, and if the dream is not at least somewhat lucid, I am generally awakened by the pain of being bitten, often to find that the pain is actually real life sore muscles or joints. I suspect that this is one of the things my subconscious made up in the dream state to explain the arthritis and fibromyalgia pain I generally just ignore under waking circumstances... in which case, a demonic tormentor seems perfectly logical to me.