Undertale/Fridge

Fridge Brilliance

• During the Neutral route: why does Asgore smash the "MERCY" button before he fights you? At first sight, you'll assume is because he won't grant you any mercy. But the fridge moment is when you realize that the MERCY button can only be used by the player, thus Asgore is stating that he doesn't want to receive any mercy from the player, not the other way around; likely since Asgore is so riddled with guilt about the things he's done to the point he feels he's beyond redemption and doesn't deserve mercy.
• As noted on his page on TV Tropes, Asgore is a played with but subverted satanic archetype, as he's shown to be the king of a species banished to an underworld who seeks to gain vengeance and uses human souls to get it, with several characteristics that are call outs to the most stereotypical depiction of devils: horns, big pitchfork, demonic-sounding name, a story of having being vanished to the underground... However, it's revealed he's an Anti-Villain and the Fallen Child is who much better fits the label. But this actually makes a lot of sense for those who have read The Bible. In the Bible, the whole Big Red Devil stereotypical appearance never shows and ironically that description is the opposite of his actual appearance, this being a beautiful angel of pure light... which also sounds like the Fallen Child.
• Some people accuse the game of a Broken Aesop because it preaches pacifism and "don't judge a book by its cover", but having characters like Flowey who are horrifically evil (which for those who have played the game know is a terrible argument) and plain horrific... but even then, it arguably strengthens the Aesop of "don't judge by appearences" because the most bizarre looking monsters are usually anti villains at worst, and the harmless looking ones like Flowey or the Fallen Child are actually the most devious.

Fridge Horror

• A 'My God, What Have I Done?' moment for the player: If you've been killing creatures throughout the game, Sans shows up near the end and informs you that LV doesn't stand for "level", but instead for Level of Violence... And EXP stands for Execution Power, not Experience. You murderer.
  • Even worse is if you decide to grind monsters for kills early in the game, in order to gain 'EXP' quickly, as you would in any other RPG. If you keep doing this, eventually there'll be no creatures left; any random encounter is met with an empty screen, and the background music will become ominous... At that point you should realize that you've been partaking in a genocide.

Fridge Logic