A sound effect from early 90s video game,
Super Mario World. This
particular sound is made when the character, Yoshi regurgitates an enemy out its mouth resulting in a noise resembling the word 'bow.' Can be used in response to just about anything said to you. Occasionally this word has a rippling effect and once triggered by one person can result in a room full of people repeating the word
over and over until everyone is in a state of hysteria.