A wow bomb consists of many repeated "wow's" in a single consecutive "wow" chain. This occurs when certain people are told something they find surprising or don't believe. The wow's can vary in length and some are emphasized more than others. A wow bomb can sound like someone trying to get their car started but instead of pistons pumping, you hear wows.
Chris: "Man I told Ben I didn't like tacos and the Wow Bomb went off."
Jeff: "You don't like tacos?!"
Jeff: "Wow! wow! wow! wow wow wow! WOW! wow WOW WOW! wow wow! WOW! WOW! WOW! wow wow wow WOW!"