At the start of the fight, Stagnox will be on the ground and will try to ram Link with its horn. He must run to its backside and use the Whirlwind to remove the gas which will allow him to attack its vulnerable backside. Eventually, it will take flight and release Blastworms, creatures that act as Bombs when attacked. Link must hit them with his Sword and use the Whirlwind to blow one of the Blastworms at Stagnox when it charges at him to flip it over. This will leave it once again vulnerable to attack.
Stagnox's name is derived from "stag," as in a stag beetle, upon which it is based. The "nox"-part may be derived from noxious, meaning toxic, which may refer to the poison gas Stagnox's rear end is emitting.
Stagnox is the only boss in the game that appears four times.
↑"The fast, heavily armored boss of the Forest Temple, Stagnox isn't your everyday beetle boss. Not only can she fly and attack with her horn, she releases poison gas and exploding larvae! Even if you wanted to take her home, she is gigantic—way too big for any terrarium!" — Stagnox Trophy (Super Smash Bros. for Nintendo 3DS/Wii U)
↑"This is the boss of the Wooded Temple. What, you want more details? All right. It has four legs, its wings make a cute sound but its groan is horrible, it releases poisonous gas and exploding larvae called Blastworms, and there's no way you'll be able to catch this big beastie in a jam jar!" — Stagnox Trophy (Super Smash Bros. for Nintendo 3DS/Wii U)