Octomon

Octomon
Octomon is a Mollusk Digimon whose name and design are derived from the Octopus. A fiendish hacker, it was discovered from the virus it used to crash a rival's research computer. It has a nasty habit of collecting things; the tips of its tentacles are affixed with claws obtained from a Devidramon's data, and it is clad throughout with Digi-Treasure which it gathered from the bottom of the Net Ocean. Fujitsumon, a kind of tiny Shellfish-type Digimon, cling to the pot it wears on its head. These Fujitsumon develop their senses, and it is thought that they have formed a symbiotic relationship so that if they sense danger they inform Octomon.

Digimon Adventure: Anode/Cathode Tamer
Octomon are recruitable enemies in the Cathode version of Temple of Darkness - Left and Right and Vamdemon's Mansion. An Octomon is also in the party of the boss of Etemon's Palace, Etemon.

Digimon Adventure 02
The three Syakomon that belonging to the Poi Brothers Digivolved to Octomon to fight a Mojyamon until Kari Kamiya and Angewomon and Izzy Izumi and MegaKabuterimon arrived with Jackie (Gennai's Chinese counterpart) to tell them that Mojyamon wasn't evil. One of the Poi Brothers and his Syakomon went to the India/China Border where his Octomon used his Spurting Ink Strike to write "We Come in Peace" on a cliff wall.

Digimon Adventure 02: Tag Tamers
Octomon digivolves from Otamamon without a digi-egg to Brachiomon in line 55, from Crabmon without a digi-egg to Divermon in line 60, and from Kokuwamon without a digi-egg to Divermon in line 69.

Digimon Tamers
Two Octomon were among the Digimon seen through the rip in the sky during Vikaralamon's rampage.

Digimon Tamers: Brave Tamer
Octomon are enemies in Dark Taichi's Crevasse.

The Candlemon card, titled "Kaimei Bokujuu", teaches a Digimon the Kaimei Bokujuu technique. Kaimei Bokujuu reduces one enemy's SP.

Digimon Adventure V-Tamer 01
Octomon was one of Lord Marine's henchmen.

Digimon World 2
Octomon digivolves from Otamamon and Syakomon and can Digivolve to Dragomon.

Octomon also appears as boss.

Digimon World Dawn/Dusk
Betamon digivolves into Octomon. Octomon can DNA digivolve with Gesomon to create Dragomon. Putting a Prissy Octomon in your Farm will unlock a Species Quest.

Attacks
 * Spurting Ink (海鳴墨銃): Shoots a bullet packed with potently toxic ink.
 * Octopus Trap (Fujitsumon)

Fujitsumon
A Digimon living within Octomon's helmet which can sense danger and warn Octomon.