lunch-bomb

informal

verb

1. to disrupt or ruin an individual's or group's lunch (typically at a restaurant) by making an unexpected appearance and prolonged conversation

2. to join an individual's or group's lunch as a last-minute, uninvited guest that disrupts or ruins the lunch's original planned intent (such as a personal or work related matter that can no longer be discussed due to the uninvited guest's attendance)

noun

1. an individual's or group's lunch that has been disrupted or ruined by an unexpected appearance and unwanted conversation by another individual or group, usually a person that one of the lunch attendees knows in another context (ex. a work related lunch that is disrupted by an old college friend)

2. an individual's or group's lunch that has been disrupted or ruined by an unexpected attendee