[I've gone through all of Mettaton's tapes that include him going into the tunnel. I found one that happened before he asked me for help finding Papyrus and Frisk.]

[I don't want to upload this. I really don't.]

The screen cuts on. Mettaton has the camera facing him inside of the tunnel, his back to the opening as he stares at the camera. His face is dull.

"Mettaton?" Frisk's voice asks from a distance, out of the tunnel.

He turns sharply as the kid walks into view, not stopping as they walk straight towards him.

"What's going on? You've been in the woods a lot, and you won't tell me where Papyrus is. Where's Papyrus?" Frisk demanded.

"I̷̹̻̎ͅ ̵̧̥̿́T̷͈̝͒̄͌Ö̶̰́͒L̸̯̫͂D̶͈̣̰̂ ̵͇͎̓Y̶̪̮̋́̓O̴̡͈̞̎U̸͔͋̕ͅͅ ̶͈̖̜͗̽̋T̷͎̼͂O̵̟̅̓ ̶̲̓̅̄N̵̗̐̓̀O̵͚̩͒̑T̴̪́̑͠ ̶̩̄̄͌F̶̠̫̅Ǒ̵̼̐͋L̸̻̪̏̽͜L̵̛̩͚̈́͝Ȯ̸͉̈͜͝Ẅ̶̱̙̞́̂̀ ̶̻̓̈͐Ṁ̸͕̪E̵̲̤͓͗̐̾!"

Mettaton stands up and runs at Frisk, leaving his camera on the ground. Frisk backs away, but his robot arms reach out and grab the kid's throat before he knocked them over.

In full view of the camera, Mettaton starts to strangle Frisk, him screaming non-stop at the while they tried to struggle. Mettaton's back was to the camera as he was sitting on the human's body, their feet kicking out behind him, knees banging against his back uselessly. Slowly, though, their movements stop.

At this point, Mettaton climbs off of them, Frisk gasping and choking for air. They cough as Mettaton grabs a large rock from nearby.

"Metta... ton..." Frisk coughs as he stands above them, rock in hand.

When he starts to swing it up behind him, the video turns black.

[He smashed the kid's head open with a rock. They died on camera.]

[He then goes and calls me to meet him the next day at Rosswood park, in Entry #39. He does this while still standing next to the kid's body.]

[He never wanted me to help find Papyrus or Frisk, he's been lying to everyone. He killed the kid. I think he might have done the same to Papyrus.]