AncientBeetlemon(AncientBeatmon in Japan) is one of the past heroes, who defeated Lucemon after saving the Ancient Digital World from the forces of darkness. An Ancient Insect-Type Digimon represents thunder/lightning (雷; ikazuchi).
One of the Ten Legendary Warriors who saved the ancient Digital World, this Digimon bears the attribute of 'Thunder'. One of the first Mega-leveled beings to exist in ancient times, its form is similar to that of various insects such as rhinoceros beetles and stag beetles. Its outer shell's hardness rivals that of Chrome-Digizoid, so that its sickle-shaped arms can lift objects hundreds of times its own mass easily, yet are light enough for it to cut through said objects. AncientBeetlemon's attribute was passed down to Insect type Digimon. Its special attacks are "Calamity Thunder", a super-electrical discharge attack so powerful that it can create super-disasters, and "Tera Blaster", an attack 1,000 times more powerful than the "Giga Blaster" attack.
- Calamity Thunder: Attacks with a calamitous thunder which brings about super-disasters.
- Tera Blaster: Attacks with a super-electrical discharge with a thousand times the power of "Mega Electro Shocker".
- His spirit forms are: the Human Spirit of Thunder (Beetlemon) and the Beast Spirit of Thunder (MetalKabuterimon).