Slugbug (also called "Punchbug" and "Punchbuggy") is a car game generally played by young children in which participants hit each other upon sight of a VW Beetle. In one form of the game, upon sight of said vehicle, a participant yells out "Slugbug (color)!" and adds "No slugbacks!" to lock that color against calling again. Once the call is completed, the participant punches another participant of his or her choice, generally in the upper arm. Another variation, perhaps a more common one, is that in which colors do not factor and in which the "No slugbacks!" call serves only to prevent the victim from slugging the first participant on the same Volkswagen.
The game is considered by some to have lost some of its appeal, as Beetles are now much more common due to Volkswagen's 1998 release of the New Beetle; some players do not consider this new model to be valid for the purposes of the game.
SLUGBUG is an acronym for the name of the Sheffield Linux Users Group and BSD Users Group.