Detective Pikachu is a Pokémon mystery-puzzle game developed by The Pokémon Company and published by Nintendo for the 3DS handheld1. The title flips Pikachu from a wordless cuddly mascot into a hard-boiled talking sleuth who partners with a human sidekick named Tim to solve cases around a place called Ryme City6. Motion capture was used to animate the character's facial expressions and speech, giving the tiny rodent a mouth that actually moves when it talks3.

The game shipped in Japan under the title Meitantei Pikachu: Shin Konbi Tanjyou, meaning Great Detective Pikachu: The Birth of a New Duo2. Fans latched onto the visual gag of a small electric mouse voicing itself like a noir gumshoe, and screenshots of the grumpy detective spread quickly across Twitter, Reddit and Pokémon fan sites once the first trailer landed4. The whole joke of Detective Pikachu is the gap between the soft cartoon body and the middle-aged growl coming out of it6.

The Detective Pikachu joke rides on the visual mismatch between the soft Pokémon design and the gravelly voice coming out of it6. People typically pair a screenshot of the character with a caption written in noir-detective phrasing, or splice audio of the deep voice over footage of the traditional cute Pikachu. Reaction posts often lean into the horror of Pikachu being able to talk at all, treating the update as an uncanny break from the original 1996 design7. When the 2018 live-action trailer landed, the common convention was to quote-tweet a Reynolds-Pikachu still with a bewildered one-liner or a comparison to another Pikachu meme4.