Coleoptera Worm Argentum is a Worm of the scarab-based Coleoptera Worm subclass and an antagonist in episodes 9 and 10 of Kamen Rider Kabuto.
Kamen Rider Kabuto
Argentum and two other Worms molted from a group of Sails Worms fighting Shadow. After Aeneus was destroyed by Kabuto with his Rider Kick, Croceus and Argentum fled the scene. However, Kabuto managed to catch up to them and destroyed Croceus and Argentum with his Rider Kick.
Kamen Rider Decade
The Coleoptera Worm Argentum is the first Worm Tsukasa encounters in the World of Kabuto while it assumes the form of a young man. After the ZECT Troopers confine it, Gatack and TheBee attempt to fight the Worm who overwhelms them in its Clock Up state. But with the unseen aid of Kabuto, the Worm is destroyed by TheBee's Rider Sting.
Kamen Rider Decade: All Riders Vs. Dai-Shocker
Coleoptera Worm Argentum was among the monsters who were part of the Dai-Shocker army in the World of Decade. They fought against a gathering of 25 Kamen Riders who formed to oppose Dai-Shocker's invasion of the A.R. Worlds.