The Brightsting Cactus is an indigenous plant to the deserts of the Kingdom of Sand, where the majority of the SandWings reside. Nearly all of the merchants at the Scorpion Den are said to peddle it, stating that "You never know when you'll need it". It is a cactus that counteracts the venom found in a SandWing's tail barb and is the only known antidote to it.
Although it is not mentioned what it looks like, it is more than likely a green and prickly plant, like most cacti. According to Blaze in The Hidden Kingdom, the plant is very common and "grows all over the desert". Also, it is unknown whether the cactus is circular, elliptical, or of some other configuration. On the cover of The Brightest Night, however, elliptical cacti are shown. These may be brightsting cacti. Sunny had difficulties pulling the arm of the cactus off, possibly because Brightsting is very strong and thick.
Its purpose is to heal wounds from a SandWing's barb venom. When the juice is squeezed on a wound it will reverse the devastating effects of the poison. The healing time span varies, from a couple of days to a week or more, depending on how long the wound was left untended. Since it is the only known antidote to SandWing venom, it is common knowledge among SandWings. In the Scorpion Den, almost all merchants sell it, showing that SandWings aren't too secretive about it. Blaze accidentally gave its purpose away to the Dragonets of Destiny in The Hidden Kingdom. It was used to treat Webs' wound, and later, Flame's; and they both survived to tell the tale.