The void : he doesn't speak

MultiMonster : I'm very annoying. I come about ever 6 doors and lockers are the safest option.

MultiMonster Prime : instead of making a static noise, I flicker your flashlight.

The Void : I lurk it the darkness. DONT YOU SHINE THAT LIGHT AT ME.

Paralysis : don't move. Trust me :)

Paralysis Prime : instead of appearing in your vision, I flicker your flashlight.

(Edit the rest of the monsters in I'm running out of characters)