You're right! No one ever notices that! But, who knows why, everyone remembers when they say the part about the demon that comes when people call it's name, but they don't say that this only happens when you do a double genocide.

Another wrong canon is that Chara has red eyes, but in the end of the genocide we can see that their eyes are brown. The only time we see a human with red eyes is at the end of the post genocide-pacifist ending, and there are 3 possible explanations:

- Chara/Frisk/or whoever that is is so filled with determination that their eyes are red, (in fact who said that red is evil? it's just too much DT. Ah another stupid headcanon is that Chara's words are always red).

- It is Frisk who has red eyes. They have their eyes closed, then they open it and we find out they are red. (I honestly don't believe this one because I think Frisk's eyes are almond-shaped, not closed)

- It can actually be Chara that got crazy or mad, after THE PLAYER killed everyone in the underground and then thought they could have their happy ending by just erasing the memories of everyone.