Concerned: The Half-Life and Death of Gordon Frohman, or simply Concerned, is a webcomic created by Christopher C. Livingston that parodies Half-Life 2. The tool that was primarily used to create Concerned was Garry's Mod, a sandbox modification which allows the player to do a number of physics-related experiments. The first issue was released on May 1, 2005. After a year, the comic ended on November 6, 2006 with a total of 205 issues. The website was shut down for unknown reasons but has since been put back up.