Undertale: Secrets You May Have Missed

Undertale has to be one of my favorite games from the last year. The lore of the game is so interesting, the music is incredible and I listen to the soundtrack when I'm at work, and Toby Fox thought of literally every playing style and adjusted the game for that. When you first play the game there's a bunch that you may miss, these are just the things that I missed the first few times I played the game and that I see others often missing when they play.

  • You are not naming your character but the human that came before you. The correct name is Chara and it will tell you that you were correct. You cannot name that human a name that belongs to another main character in the game.
  • Flowey is stalking you throughout the game if you go retrace your footsteps.
  • If Toriel somehow manages to kill you, her eyes will widen and she'll cover her mouth as she didn't want to kill you. As you can tell when your health gets low, all her attacks miss you.
  • If you wait in the room Toriel instructs you to stay at, she'll call you at regular intervals.
  • If you call Toriel on the phone and call her mom then flirt with her twice you get some unique dialog. And she'll mention it at the end of the True Pacifist ending.
  • If you go back to your room when Toriel instructs you to, Asgore will play to tell you to wake up and you must stay determined.
  • You can make the froggets have characters get rid of the yellow indication that they can be spared for the reminder of the game. But if you ask for it back, they will change the color to pink. Later in the junkyard, you'll find a pile of yellow names.
  • Papyrus once you have his number has something to say about every area if you call him.
  • Papyrus will confuse himself on the instructions of the colored tile puzzle if you ask for clarification. If you ask for clarification twice, he'll let you just pass without doing the puzzle.
  • In the True Pacifist ending, if you go all the way back to the beginning of the game you will see Asriel caring for some flowers.
  • You can skip the Muffet battle if you save a Spider Donut from the ruins.
  • The game doesn't start in 201X, that's the year Chara fell into the underground.
  • Mettaton is Napstablook's cousin and the head of the human fan-club.
  • Monsters only age when another generation of their family is still living. You learn this from the hammer of justice at the end of the pacifist run.
  • Toriel will send you multiple texts at the end of the pacifist run. One for every area until she decides that she's sent enough.
  • It's possible to get through the game without encountering Jerry.
  • The game as various random events that can occur including "The Forgotten Ones" characters that appear if you retrace your path but depending on the FUN value you get when you start the game, they may not appear at all. The Forgotten Ones are all Gaster followers.
  • Temmie (shopkeeper) is the only NPC that doesn't have different dialogue after the final battle.
  • You cannot get the true pacifist ending if you did a renegade run previously. Chara will always pop up and say it's all a lie.

Do you know of anymore that I may have missed?