Ghost Stories From Japan Episode 48 : Forbidden slides in my school

This is a story from my early elementary school days.
I was what is called a " latchkey child," and because I felt lonely without anyone when I went home, I always stayed at school until late in the evening to play with my friends.
Most of the time, I would play ball on the playground with them.
Even so, after about 4:30 pm, all of them would leave.
When the playground was empty, I would play on all the equipment before leaving.
The bars, the swings, the vaults, the climbing bars, and last but not least, the slide.
The slide had a rather unusual shape.
At the top of the ladder, there was a V-shaped split with two slides.
It looked like an elephant with two noses.
They were supposed to be made so that two children could slide on them at the same time, but only the one on the left was actually able to slide.
The right slide was blocked by a plywood board.
And a piece of paper was pasted on it, which said "keep out"
According to the teacher, it was because there were spikes on the slide, and some children got hurt.
However, as you know, it is children who are tempted to do things when they are told not to.
At dusk, everyone had gone home, and I was alone on the playground.
No one would be watching me now, I could not suppress my curiosity.
With a pounding heart, I climbed over the plywood and slid down the "keep out" slide.
Since it is a slide, it should reach the bottom in an instant.
But it seemed longer than usual.
I thought, "what ?, why is that ?"
And then, something happened that I hadn't expected.
The next moment, a big red face appeared from the side of the slide, and came at me with a terrible cry.
I honestly had no idea what had happened.
I was just so startled that I ran away from the slide as soon as I reached the ground.
The red face was on the side of the slide, just at the height of an adult face.
But it was much bigger than an adult's face, and it was not a human face.
It was red and big, and now that I think about it, I think it looked like a lion from a lion dance, like a namahage in Tohoku Region ... like an monster face, anyway.
I looked at my feet, thinking that someone had come out wearing an monster mask to surprise me.
But no matter how I looked at it, the red-necked monster was floating in the air.
The next moment, the monster was chasing me.
It floated in the air, and chased me from above.
I was so scared that I ran away.
From behind me, I could hear its voice.
I screamed, "teacher teacher !", and ran toward the school building to ask for help in the staff room.
Strangely, however, the school building was locked and I could not enter, the school gate was also closed.
While I was running around the school building, the giggling monster was slowly, but surely chasing me.
Its red mouth was gaping open and drooling.
I was sobbing, but no one was helping me.
Or rather, there was no sign of anyone other than me and the monster.
And I could neither enter nor leave the school building.
I started to think, that the monster was going to eat me....
Running and running, soaked with sweat and tears, I returned to the original playground.
Then, I went up the slide.
Somehow, I thought that if I went down that slide again, I would be back to normal, so I went down the slide on the left side, the opposite side from before.
It was the one that was not "keep out" one.
As I went down the slide, I felt something had changed.
There was a flow in the heavy air...a strange feeling.
When I turned around, the red monster was gone.
I was able to enter the school building, the teacher was in the staff room, and the school gate was open.
And then something even stranger happened.
The two slides that had been attached to the school were now only one.
I asked my friend and the teacher, "wasn't there two of those slides ?"
But they all said that there was only one slide from the beginning.
Indeed, no matter how one looked at it, there was only one slide that went down.
However, as far as I remember, there were definitely two, and I remember playing with my friends and checking the "Keep Out" paper and boards.
The teacher also explained about the "Keep Out" of that slide.
Above all, I still vividly remember that terrifying experience with the red face.
And yet, no one but me knew that there were two slides....
I still don't know what this memory or experience was, and I try not to think too much about it.
But this is my scariest memory from my childhood.