Seahomon

Seahomon is a Sea Animal Digimon whose name and design are derived from the seahorse. It is an Armor Digivolved form of Armadillomon through the Digi-Egg of Light who dwells in deepest depths of the Net Ocean. Its body is smaller due to the water pressure, but it regains its size near the ground.

Digimon World DS
Seahomon digivolves from Ankylomon if it's holding the Digi-Egg of Light.

Digimon World 3
Seehomon can only be found in Asuka's Central Sector, in the Central Park's seabed towards Bulk Swamp in the South Sector if you have Kumamon at lvl. 45. If you give him Zodiac and Tempest Arm, he will make Prominence.

Digimon World Dawn/Dusk
Seahomon digivolves from Armadillomon with the Digi-Egg of Light when he is at Lv27+ with 2700 or more Dragon EXP

Attacks
 * Prism Rainbow
 * Dragon Noise (Dragon Drop)