Fart Arrows

Fart arrows explode into a cloud of nasty smelling yellow smoke, most likely sulphur, when they hit something. They are used by the Hunters of Artemis in the game of Capture the Flag (in The Titan's Curse) and Thalia calls them Fart Arrows. These arrows are very useful for temporarily stunning enemies and clouding their vision.

They also are known to "smell like rotten eggs" to Percy.