This titanic enemy is essentially a much stronger cousin of the Blue Shield Eel. It uses a mine attack which can bounce off terrain. This enemy can give severe damage to melee characters overtime. Due to the mass amount of White Shield Bats, they may distract players from this enemy and lead to massive damage taken. This big enemy only appears once in the 5th screen, due to its huge LP and attacks that reach up to 180 damage. Ranged weapons and/or great DPS melees would help to dispose it. Poison and Ice type weapons work fine too. There is actually an easy way to defeat this enemy. First, lure it out of the water as it slides through the terrain. Keep luring it until it reaches the boss sign. It's really vulnerable as it couldn't move any further. During this helpless state, drag a Sniper, Gunner, or Magician (Preferably with Fire type weapons or weapons with piercing capabilities if the ceiling is too low), and defeat the enemy in no time without getting damaged.
This could also be considered a hidden boss, as it only appears with enough water in the screen, has Freeze resistance equal to most bosses, and it is incredibly powerful as it also managed to out-class the Submarine Shrine Boss (in LV, LP, EXP, and gold). Because this enemy only appears on one screen, with one occurrence, and it only has a small chance of appearing, it is the rarest enemy in the game. This enemy also is the only one in the game to have a perfect chance of an item dropping, which is the Poison Charm 4.