The Huge Hermit is the first boss from Metal Slug 3.
Originally a hermit crab on Dr. Moureau's Island before it grew to a huge size, the Huge Hermit is one of the results of the nuclear strike on Dr. Moureau's Island. The rebels later capture the gigantic crab and use the shell as a tank, allowing the crab to fire the cannon.
The players have to keep going to the right while shooting at the boss,. The crab will attack by shooting two fireballs from the tank, while also trying to destroy the bridge. After taking enough damage, the crab will reveal a large cannon, which fires large shells that can destroy parts of the bridge. If the player took the Metal Slug route (through the swamp), They will face the crab with the SV-001 Type-R that faces backwards, which is the easier way. However, if they took the other routes (underwater or the sewers) they will encounter and fight the crab with the Slugnoid. While they receive 2x the firepower with the Slugnoid, the players have to take care and avoid getting hit.
Mini Hermit: There is a mini version of the Huge Hermit in Metal Slug Defense as a special reward for 20 million downloads. Its claw can deal high damage meaning it can kill most enemy troops in one hit, but it will take at least 2-4 hits to destroy a tank. Its cannon remains unused. Despite Mini Hermit walking on land, it still has a wave of water around the hermit. When this unit dies, it will sink on land and explode.
- If the players takes the Slugnoid route, the Slugnoid will fire a red-colored fat Iron Lizard as its cannon.
- When the players fight the Huge Hermit, it appears to be walking. However if the players defeat the boss, it will sink like its deep water.
- The fight with the Huge Hermit is similar to the penultimate boss of Sonic 3 & Knuckles, in that the platform behind the player is constantly being destroyed as the boss is firing at the player or players.
- In Metal Slug Defense and Metal Slug Attack, it appears as a boss. In the early stages that it appears in, it loses its ability to shoot either the fireballs or the cannon but keeps its ability to do the rushing claw attack. The other version that appears in the extra world of MSD in the 1.36 patch can use the fireball cannons but it can't rush forward. In the Hermit Boss fight, it will destroy parts of the dock, instantly killing anything it touches. If it gets to the player's base, it will result as an instant-game over, as it will destroy the base instantly.
- The Huge Hermit in Metal Slug Attack is deployable as a unit and it has the 4th most base HP in-game at 32,000 HP.
- Similarly to the Mini Hermit in MSD, the deployable version of the Huge Hermit has a wave of water around it.
- Before the Huge Hermit became deployable in Metal slug Attack, it was once deployable in the game "Battle Cats" in collaboration with Metal Slug.