Now, I have had the stupidest nightmares (most in my childhood, since I RARELY get bad dreams nowadays), but I think my stupidest one was one where I was playing Sonic Adventure (I was around 3...?) and all of a sudden I had to use the bathroom really fucking badly, so I do so. After I'm done, my toilet literally comes to life, grabs me with an arm, and drags me down the flusher where I drown. So yes. A monster TOILET!!
My scariest was when I first watched marblehornets, and was introduced to the Slender Man. I shat bricks every time I saw him in the series. I went to sleep, trying to tell myself he wasn't real (obviously he isn't)
Next thing you know, I have a dream that my friends and I are on a camping trip. We all go to sleep at night, and when I wake up in the dream, my friends are gone. I decide to go iinto the forest to look around, with my flashlight in hand. I see an old cabin and I suspect they were all in there. I look behind me to see someone standing there. I drop my flashlight and pick it right back up to see if he was there, but he was gone. I assumed it was an illusion. I go inside the cabin and find myself going into the basement where I find my friends... dead. They were cut up and hung on a wall, and there were messages written in blood saying "I will find you" or "no eyes" or that oporator symbol, and loud, disturbing noises (no, not sex) was ringing in my ears. I look behind me to see that Slender Man was right there. I tried to run but it was too late, and I woke up right after that.
You gotta love nightmares folks. They're either hillarious or truly frightening.