Mecha Gear FISH is a previously PlayStation-exclusive boss that can be encountered in Gaia's Garden as part of the quest Foul Play.

Mecha Gear FISH
It can't be!
-Monster Fibula report

Appearance

Mecha Gear FISH is an Angler inside a round fishbowl inserted in a mech's cabin. The mech has two legs, two pairs of guns around the cabin, and a pair of wings to the sides of the cabin that have five missile launchers on their backs each.

Combat

The only way of doing meaningful damage to this boss is attacking the Angler itself. To get it down from the mech, the player has to first break both of its legs with any attack method. Mecha Gear FISH will rest after every attack, making the legs flash red and become more susceptible to breaking. When both legs are taken down, the boss jumps in front of the room's upper door and repairs itself while having an aura that pushes the player back and shooting missiles from above. If the player sits under the boss, in front of the upper door, they can get the missiles to hit the boss, breaking it and causing the Angler's fishbowl to drop from the mech.

Phase 1

• Jumps in front of the room's upper door, then dashes towards the player in a straight line, leaving icicles in its path. When it finishes the dash, it jumps into the air and tries to stomp the player once, causing a big Cold explosion.
• Fires two slow, non-damaging Wave projectiles that stop in front of it and quickly fire themselves as harmful and fast projectiles towards the player just like Fae Round.
• After both of its legs are broken, it fires Heat missiles into the air until they are repaired or the boss itself gets broken. The missiles are aimed at the player, indicated by small red crosshairs.

Phase 2

• Jumps to the center of the arena, charges with a green aura and jumps four times in an attempt to stomp the player. Every time it lands, it causes a Wave shockwave and multiple damaging circles to go out in all directions, with its final stomp having a bigger area of effect along with more projectiles. It uses this attack every time a new phase begins.
• Dashes twice before doing its Cold stomp.
• Fires two pairs of Wave projectiles.
• Fires Heat missiles at a faster rate.

Phase 3

• Dashes thrice before stomping.
• Fires two Wave projectiles, then one, and finally three in a row.
• Wave stomps six times instead of four. It also jumps faster than before.
• Heat missiles are fired even faster.

Strategies

• Its Cold stomp is easier to dodge by dashing vertically, in contrast to its Wave stomp that can be dodged by dashing sideways.
• Whenever the boss dashes, make it dash close to the walls so the icicles don’t reduce your mobility as much.
• Go immediately to the upper door after breaking its legs, or use a Dash Combat Arts to go through its pushing aura.
• The boss' footing is quite unstable, giving it a tendency to slide to the sides after every attack. You can avoid this by dodging to its opposite direction.

Location

Gaia's Garden

• Big Boss

Gallery

• 
  Mecha Gear FISH dashing and generating icicles in its path.
• 
  Cold stomp.
• 
  The orb projectile.
• 
  Wave stomp.

Trivia

• Its design and name are very reminiscent of the Metal Gear, a series of weapons from the eponymous videogame series, most notably Metal Gear RAY.
• The room the boss is fought in is also a reference to the character of the same name from Metal Gear.