|This article is about a/an set of Headders in Tensou Sentai Goseiger.|
Seaick Brothers (シーイックブラザー Shīikku Burazā) are a trio of submarine style Headders that combine onto Gosei Great to form Seaick Gosei Great. They are composed of the Manta Headder (マンタヘッダー Manta Heddā), the Sawshark Headder (ソーシャークヘッダー Sōshāku Heddā), and the Hammershark Headder (ハンマーシャークヘッダー Hanmā Shāku Heddā)
Manta Header is a manta ray mecha. Forms the head of Seaick Gosei Great and can shoot blue energy blasts from the center. When attached to the Spear of Ground Gosei Great, he shoots out a giant whirlpool of water.
Hammershark Headder is a hammerhead shark mecha that's a member of the Seaick Brothers.
Forms the left hand of Seaick Gosei Great.
Sawshark Headder is a saw shark mecha that's part of the Seaick Brothers. Forms the right hand of Seaick Gosei Great.
Seaick Gosei Great
After combining with the Seaick Brothers, Gosei Great becomes Seaick Gosei Great (シーイックゴセイグレート Shīikku Gosei Gurēto) and the Goseigers will announce: "Seaick Gosei Great! Advent!". Seaick Gosei Great can scan an opponent's weaknesses using the high sensitivity sonar Seaick Analyze (シーイックアナライズ Shīikku Anaraizu) on its right eye and can headbutt opponents using it's head. By inserting the Victory Charge Card in the Tensouder to initiate Seaick Gosei Great's final attack the Seaick Strike (シーイックストライク Shīikku Sutoraiku), where it shoots rows of holographic cards from it's hands and head to the opponent paralyzing them in place then finally do a combination hammer-punch/downward slash move.
Another Seaick Gosei Great
When using the Manta and Hammer Headders as hands and the Sawshark Headder as chest armor, Gosei Great becomes Another Seaick Gosei Great (アナザーシーイックゴセイグレート Anazā Shīikku Gosei Gurēto) and the Goseigers will announced: "Another Seaick Gosei Great! Advent!". First debuts in Epic 18.
- The Seaick Brothers can unite with Landick Brothers, Skick Brothers, Gosei Great, and Datas Hyper to form Hyper Gosei Great, and further with Groundion and the Knight Brothers to become Ground Hyper Gosei Great.
- The Hammershark and Sawshark Headders can unite with the Taka Headder, Landick Brothers, and Gosei Great to form Sky-Land-Sea Gosei Great.
The Greater Power of the Goseigers allows GokaiOh to summon the Gosei Headders, namely the Seaick, Skick and Landick Brothers as well as the personal Headders of the five Goseigers. The Headders are used to charge at an opponent in a finishing attack called the Gokai All Headders Great Charge (ゴーカイオールヘッダー大進撃 Gōkai Ōru Heddā Daishingeki), which was used once to destroy a horde of Non-commissioned Officers Sugormin.
- The Manta Headder helmet resembles the hat of a pirate captain, with an eyepatch that acts as a scope to lock on to targets, something that is referenced during Gokaiger Goseiger Super Sentai 199 Hero Great Battle.
- Unlike the other tribe brothers, the Seaick Headders can only be used by the other Goseigers during battle because there is only one Seaick Tribe member in the team.