(Repeat message)
I repeated all the steps you described, but found nothing. I jumped into the pipe, sat there for 5-6 minutes, then went into the menu and started poking at the graphics settings. I repeated this about 12 times, but nothing happened (After sitting there for 34 minutes, according to the recording). Maybe you saw a spider? All black, with spiky limbs (Scroll down a bit here). Maybe I'm wrong, and I was just unlucky to see it.