Hollow Knight is a 2017 Metroidvania developed by Team Cherry, set in the ruined kingdom of Hallownest. Scattered through the world are 46 Grubs trapped in glass jars, which the Knight can free during exploration. Rescuing them earns rewards from the Grubfather and remains one of the game's most beloved side activities because of their joyful noises. Clips of the sound spread through YouTube, TikTok and gaming soundboards, where the chirp became shorthand for wholesome happiness and a successful little rescue.