History Fridge / Undertale

* Sans is a skeleton, so [[spoiler:why would he bleed when the Fallen Child attacks him? Well, if you refuse Sans when he offers you ketchup in Grillby's, drinks it all. Sans didn't bleed, he was leaking ketchup.]]

* The prophecy described on the walls of Waterfall and mentioned by several characters is ambiguously interpreted. Some believe the Angel will free them all from being trapped in the Underworld, while others see it as a macabre Angel of Death who will free them from their eternal malaise by ending their lives. [[spoiler: This reflects the two extreme paths: The Pacifist ending which ends with Asriel using his power to unseal the barrier, freeing the monsters without ending any more lives; and the Genocide ending, where the player eradicates all of the monsters in the Underworld themself.]]

* If you [[spoiler:spare Flowey in a neutral run]] or [[spoiler:complete a pacifist run altogether]], said character suddenly [[spoiler:becomes a lot nicer, admitting he's become an utter monster, even reverting to his previous self of Asiel in the pacifist version.]] Why? [[spoiler:Well, because Flowey's evil isn't Flowey. It's the Fallen Child, aka the personification of your own bloodlust and the desire for strength simply to be strong. In a neutral run, the very fact you've shown the capacity for Mercy weakens it enough for it to lose control over the SOULs and die altogether if you show compassion to even the monstrous BigBad, and in a pacifist run you've become the anti-Child due to your sheer determination to do the opposite of what it wants, and is has long outright ceased to be, leaving only Asiel in Flowey]].

* Off to the side in New Home is a row of coffins marked with color-coded hearts. You can only reach the red one, on the far left, which is marked with the name associated with the save file. It's empty, presumably to contain the player character. [[spoiler:Except that the name it's marked with ''isn't the player character's,'' it's the Fallen Child's. Where did the body inside go, and why is it marked the "wrong" color?..]]

* Near the end of the Genocide path, [[spoiler:the player finds the Real Knife in place of the Worn Dagger. Although it's likely Toby already had something like this in mind, this item began as a rumor about the demo version. To find whether it was true or not, people went on a rampage through the ruins. After it was disproved, people hoped it eventually would be implemented. And when the Fallen Child gets their hands on it, they're all left satisfied. It sure turned out to be a symbol of the bond between players and murderous little avatar.]]

* Near the end of the Genocide path, [[spoiler:the player finds the Real Knife in place of the Worn Dagger. Although it's likely Toby already had something like this in mind, this item began as a rumor about the demo version. To find whether it was true or not, people went on a rampage through the ruins. After it was disproved, people hoped it eventually would be implemented. And when the Fallen Child gets their hands on it, we're all left satisfied. It sure turned out to be a good symbol of the bond between players and murderous little avatar.]]

* Your room in Toriel's house has lots of toys and shoes. Plus there's a chocolate bar in her fridge. Clearly these all belonged to kids that she rescued before.

* Napstablook's name makes little sense when you first meet him, but when you get to his house you discover he's a music aficionado. [[spoiler: He's a Napster bloke.]]

* [[spoiler: Flowey's final form has a load of attacks, but the SOUL WARNING Attacks are all different weaons you can equip during the game. This is because he's using the souls of the other six children, who used these weapons before dying.]]

* Sans and Papyrus. They're named after typefaces (Comic Sans and... Papyrus) that get a lot of hate in the design world for being overused. Similarly, the characters get little respect when they show up (they're upset at their limited appearance in the demo, and the narrator shuts them down in the Steam Greenlight trailer). Their skeletal nature might also be a VisualPun of the "overuse" of their namesakes. Yet, by virtue of their enigmatic nature, the characters already have a fan following.

* Toriel introduces you to the puzzles in the ruins, but when she leaves you on your own, she expects you're going to stay put until she comes back. So why bother with the explanations? (And why bother with resetting the puzzles, which apparently she had to do while she was on her way to find you?)

-->''Strive every day to increase your "LOVE." Remember, "LOVE" comes easiest from friends and family. =)''