The Man With No Name's shotgun
From Jenny Everywhere Wiki
The Man With No Name's shotgun was a “shotgun that [could] alter the fabric of reality”, owned by the dimensional traveller known simply as the Man With No Name. It “technically didn't exist” in any universe other than the one where it had been constructed, and was thus impossible to damage outside it. It was, however, also capable of shooting ordinary, deadly bullets. The Man With No Name used his shotgun to defend himself against a Brotherhood of Multiversal Oneness assassin armed with a “samurai sword” that could supposedly cut through anything, ending up shooting his attacker. (COMIC: The Legend of Jenny Everywhere)