Type-12B capsule (5e Equipment)
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Type-12B capsules, also known as Type 12-B Hollow-Tip Rockets, were manufactured by the Locris Syndicated Securities and was designed to be used by the Model RDP-12 Rocket Launcher.
It was a type of stun rocket dart usually filled with some kind of knockout gas or nerve agent. Typically the Type-12B rocket was filled with the FGA-583 nerve agent.
You load this missile to a MM9 Mini Concussion Rocket Launcher. When you shoot the missile, you do not make an attack roll. When the missile lands, it emits a thick cloud of gas that creates a heavily obscured area in a 20-foot radius. When a creature enters the area of the gas or starts its turn in the area, that creature must make a DC 15 Constitution saving throw. On a failure, a creature is stunned for 1 minute. A creature has advantage on the Constitution saving throw if it holds its breath. The gas is both an inhaled chemical and a contact agent. A creature which fails its saving throw against the gas can make a new Constitution save at the end of each of its turns, ending the effect on itself on a success.