The GEKKO is a small mech featured in Metal Gear Solid 4: Guns of the Patriots for the PlayStation 3. They were developed by the ArmsTech corporation, creators of Metal Gear REX, and are employed by various companies as a means of replacing tanks or other heavy artillery when conducting armored warfare. While not the titular Metal Gear model of MGS4, they share strong similarities with previous Metal Gears.
Two GEKKO will occasionally appear in the background of the Shadow Moses Island stage, sometimes even jumping onto the partially collapsed wall of the stage's background to watch the fighters. However, they do not have any impact on the battle itself, they simply serve as a reference to MGS4. A trophy of this weapon can be unlocked by defeating All-Star mode with ten different characters.
A Metal Gear with a pair of animal-like legs. Gekko are mass-produced weapons used in military combat. Its distinctive legs allow Gekko to move at high speed, jump incredible distances, and even cling to walls, giving it unprecedented mobility. Other noteworthy features of this model include prehensile tentacles strong enough to pick up soldiers and its signature deafening roar.
- The GEKKO, along with Metal Gear REX and Metal Gear RAY, appear on Shadow Moses Island in Metal Gear Solid 4.
- The GEKKO is the second appearance in a Smash game before its actual game (the first being Roy from Fire Emblem). SSBB was released before Guns of the Patriots.
- The "deafening roar" mentioned in the trophy description is more akin to the mooing of a cow. The sound effect is intact in Brawl. Considering this, the description is likely tongue-in-cheek.