Toy land-mines have definitely gone out of fashion. Hakes Collectibles explains that the toy was "designed with a trip wire which you were to attach to tree or other stationary object and when wire was bumped, grenade would shoot in the air and cap would fire on base." Also, the toy was "similar to actual weapons used in the Vietnam war."
Baseball caps may not seem like dangerous weapons, but several caps are available for purchase that advertise their potential for combat.
The BudK Night Watchman Sap Cap Extreme contains "a pocket of unique impact material that is 100% the density of lead and which is sewn into the cap." So you take off the cap and smash someone over the head with it.
The FAB DEFENSE "GOTCHA" Cap has a ninja weapon hidden inside it so that you will "never be caught empty handed."
Back in 1947, there was a lot of speculation in the press about a new secret weapon that was supposed to be as "awesome in its effects as the atomic bomb." Turns out the weapon that was the source of the rumors was the Tsunami Bomb -- a device for creating artificial tsunamis to wipe out enemy forces on land.
The Mexico Ledger (Mexico, Missouri) - June 16, 1947
Wikipedia has a brief article about the Tsunami Bomb, but otherwise there's not a lot of info about it online.