Look up the creepy background music that goes with it in the NTSC-U version...

Also, a direct english translation of the text says

Fun = Infinite
SEGA Enterprises
Majin

So, nothing bad, except it's signed by MAJIN. That means the Devil (god of demons). This happens when you enter a certain code in the sound test on Sonic CD. Imagine being me though, like 11 playing Sonic CD and playing with sound test and THIS comes up. Haunted my dreams for like 2 months.

That face is so familiar looking at it again! It's

The scary thing is that this actually exists... Its not just some creepypasta.

I found out that it was supposed to be a creepy yet effective form of DRM. Basically,if the game ROM didn't match the checksum, the game would start to this screen to stop piracy. Like other unused images etc, it can be found using Sound Test on a legit copy.

This is a very old secret.
How did you just discover this :I

Quote from Shensurei

This is a very old secret.
How did you just discover this :I

I discovered this in the 90s when I was 11. You would have known that if you actually read the post.

Quote from The_Stick

I discovered this in the 90s when I was 11. You would have known that if you actually read the post.

My bad, I missed that when I read through the first time, but I'm still not seeing what the big deal is with this all of a sudden...

Informing the new masses?

But that's what tumblr is for
To tell people about really weird/interesting things that happened in the past that hardly anyone remembers

What is this..."tumblr" you speak of?

some weird little website for weird little people.
I have one.

Quote from Xero

What is this..."tumblr" you speak of?

Click here

It's a blogging site.
Edit:

Originally Posted by Shensurei
some weird little website for weird little people.
I have one.
You ninja'd me in the same minute I posted mine.

Quote from Hewitt

Consider the populace, well informed.

Dat redneck voice damn.

You know this is still haunting me.

Well, my main question is, why did Sega even use that in the game?
Also I went on Youtube to check a vid of it. I've heard that music before. I'm really sure I did, and in a different game. I don't remember which game though...