Fullmetal Hugger

Fullmetal Hugger is a massive crab boss who appears in some of the earlier Mana games. It first appears in Final Fantasy Adventure. Fullmetal Hugger generally has a large rocky body, with the main part having a reddish color and its legs being either light green or dark blue in color, depending on the game.

Final Fantasy Adventure/Adventures of Mana
In Final Fantasy Adventure and the Adventures of Mana remake, it is named Metal Crab, and it is fought within the Hidden Waterfall. In the smartphone and PlayStation Vita releases of Adventures of Mana, defeating the Metal Crab earns the player the "Crab Crusher" achievement.

Trials of Mana
In Trials of Mana, Fullmetal Hugger is the first major boss, and it is encountered in Cascade Cavern where it holds a seal over Lumina. A stronger variant is also fought when the Chosen is neither Kevin nor Charlotte.

Legend of Mana
In Legend of Mana, its name was changed to Fullmetal Haggar, who is encountered at Madora Beach during the "Summer Lovin'" quest

Sword of Mana
In Sword of Mana, its name is formatted as Full Metal Haggar, and it is fought in Cascade Cave. When Full Metal Haggar is defeated by the Hero or Heroine, it retreats into the Boison Vine's stomach, and the hero then has to fight Boison Vine.

Echoes of Mana
The Trials of Mana iteration is fought as a boss in Chapter 4: Soaramame, itself a corrupted memory of the world seen in the source. It is weak against attacks from Dark-aspected characters, but immune to Light attacks.