The Seacons were created for off-world combat and operations on planets with liquid water oceans. The six members can combine together to form Piranacon. They were summoned to Earth by Shockwave to help defend the Decepticons under-water base where he outfitted them with modes that resembled some of Earth's aquatic lifeforms.
Beast Wars II & Neo
In the Japanese Manga they are called Space Pirate Seacons or Seacon Space Pirates, and steal treasure, energy and power. The team also only consisted of five members instead of six: Halfshell (Snaptrap), Scylla, Coelagon (Skalor), Terrormander (Seawing), Sea Phantom (Overbite). They can combine to form God Neptune (Piranacon). They are all the Beast Wars counterparts to the original Seacons, however Tentakil was replaced with a female version Scylla.
In the Japanese Manga the Seacons are a horde of mindless robotic drones led by Turtler. They serve Devil Z and Overlord. The Seacons consist of: Turtler (Snaptrap), Lobclaw (Nautilator), Overbite, Kraken (Seawing), Gulf (Skalor), Tentakil. They can combine to form King Poseidon (Piranacon).