When a character consistently established to be far from the sharpest tool in the shed, somehow outsmarts a character who thinks of themselves as being intelligent, resulting in absolute shock and humiliation.

The Good Place: For context, Season 1's finale revealed >! that all the characters are in Hell, and the "Good Place" is their personalized torture !< where the 4 humans Eleanor, Jason, Chidi, and Tahani are meant to >! drive each other mad with their conflicting personalities !< Only problem is, >! One of the characters inevitably figures out they're in hell, in spite of billion year old demon Michael's best attempts to fool them, forcing him to reset their memories !< 

Jason is established as the least intelligent human of the 4. He constantly mixes up words, thinks every problem can be solved with a molotov cocktail, and believes the Jacksonville Jaguars are the best football team on Earth. Yet, >! in one iteration !< he manages to deduce the big twist of the show before any of the other characters, based on the fact that none of the TVs have the NFL Redzone channel, which is >! pretty weird for a place supposed to be his perfect heaven !< Needless to say, >! Michael isn't too happy that he couldn't even fool JASON of all people into thinking they were in Heaven !<

  
Deltarune: Throughout the game, Berdly has prided himself on being the class nerd: Creating the image of being a studious if stuck-up genius who's always the smartest person in the room, and has an answer to every question. Meanwhile, Susie is the kind of person who has to google if hardboiled eggs hatch. Yet, when the gang encounters a simple puzzle, Berdly struggles to figure out how the shapes can possible fit together, while Susie has the much simpler idea to just pile them all in the square without worrying about overlap, which actually works. Seeing Susie somehow solve a puzzle before he did absolutely breaks Berdly's entire worldview. >! This forces Berdly to confess that he's not actually that smart, he's just high on the attention he gets from people who think he's smart, and his friend Noelle does all his homework for him !<

(Hilarious trope) "The IDIOT figured it out?!"