Super Mario RPG’s Hidden Boss Explained

Super Mario RPG and its remake have a secret, true final boss that some players will never even encounter. This is a classic RPG tradition – many games in the genre, including several other Mario RPGs, have hidden bosses separate from the ones that appear during the course of the main story. Some games have multiple secret bosses that can be unlocked throughout the campaign, while others can only be fought after watching the credits roll. Super Mario RPG only has one, but he more than makes up for it by being incredibly difficult.

Super Mario RPG‘s hidden boss is harder to unlock than any other enemy in the game. And even after that, the challenge is only getting started. He’s tough to beat, requiring careful consideration of equipment, items, and special attacks used. The remake even adds a powered-up version, making him stronger than ever before. Here’s how to find him and fight him, and an explanation of why he exists.

Super Mario RPG’s Secret Boss Is Culex

And His Powered-Up Version Culex 3D

Super Mario RPG‘s secret boss is named Culex, and the remake uniquely includes a powered-up version called Culex 3D who can only be unlocked after completing the game. Culex has the torso of a muscular, purple man with golden wings and ram horns, but his lower half resembles a cluster of crystals with a black, wispy tail extending beneath it. His name is derived from the real-life Culex genus of mosquitoes, and from certain angles, his tail resembles a mosquito’s stinger.

The original version of Culex, who’s functionally identical to the first one fought in the remake, has 4,096 HP, and is accompanied by four elemental crystals that bring the total enemy HP pool up to 12,396. In the SNES version of Super Mario RPG, Culex’s HP easily dwarfs that of the game’s regular final boss, and he could be called the most powerful boss in the game. In the remake, however, Culex’s 2D version pales in comparison to his 3D version, although the strategy for beating both of them is largely the same.

How To Unlock And Beat Culex In Super Mario RPG

The first version of Culex can be unlocked once Mario reaches Monstro Town, fairly late in the game’s main story. Within Monstro Town, there’s a cliffside with several doors carved into it. One of them appears to be locked, and if Mario interacts with it, it’ll simply say it’s been sealed.

In order to open the door and fight Culex, Mario needs the Shiny Stone, which can be obtained in nearby Moleville. The party should head back in that direction and explore the unmarked houses until they find a mole selling fireworks. They can buy some for 500 coins, then head to the right of the house to find a mole girl standing near some boxes. She’ll offer to trade them for the fireworks and, if they accept, present them with the Shiny Stone needed to unlock the way to Culex.

With the door unlocked, Mario and company may enter, at which point Culex will emerge from the shadows and introduce himself. He offers them an opportunity to fight him, which they may accept or decline. If the party’s not fully kitted out with the best gear available and all their HP, they might want to rest up before they return. The best playable characters in Super Mario RPG should be placed in the party: Mario, Princess Peach, and Geno make up a good composition for this fight. However, Mallow can also be useful, as his elemental attacks can exploit the weaknesses of Culex’s crystals.

Culex’s elemental crystals do the majority of the attacking. Culex has a few unblockable attacks himself, but also focuses on negating any buffs the party might use. Peach should prioritize healing, but if no one needs to be healed on a particular turn, she should use her non-elemental Psych Bomb special to deal damage to Culex and all four of his elemental crystals at once. Meanwhile, Mario and Geno can focus on taking out the crystals one at a time, reducing Culex’s ability to deal damage. Finally, they should turn on Culex himself, and burn his HP down until the fight is over.

Unlocking Culex 3D is a little harder, and can only be done after beating the main story. Super Mario RPG has a post-game in which players can face off against more powerful versions of all its bosses, Culex 2D included. As they go through these fights, the party will eventually come up against Duel-Ready Johnny, an upgraded version of Johnny, on the Sunken Ship. After beating Duel-Ready Johnny, they’ll receive the Extra-Shiny Stone, which unlocks the door in Monstro Town once again. This starts the fight with Culex 3D, a more powerful version of the secret boss. However, the strategy for beating him is much the same.

Culex & Culex 3D’s Rewards In Super Mario RPG

Beating the 2D version of Culex during the main game rewards the party with the Quartz Charm, a handy little accessory. The Quartz Charm prevents instant-death attacks like Jinx’s Silver Bullet, and also increases the wearer’s physical and magical attack damage by 50%. Beating Culex 3D, however, grants the party a Crystal Shard. This item is functionally useless, and mostly serves as a trophy to represent the party’s victory. However, beating Culex 3D is necessary for 100% completion of the Monster Log, and he’ll probably be the final target for most players.

How Culex Is Connected To The Final Fantasy Series

It’s pretty obvious that Culex doesn’t really fit in with the rest of Super Mario RPG. For one thing, the first version of him that appears in the remake is an SNES-style 2D sprite, but moreover, he’s just an oddly menacing character for such a silly and lighthearted game. As it turns out, Culex was included as an Easter egg referencing the Final Fantasy series, which, like the original Super Mario RPG, was developed by Square Enix.

There are a number of other references to FF sprinkled throughout the two boss fights. Culex can cast Meteor, an ultra-powerful spell and a staple of FF final bosses. The special theme that plays during the battle against Culex is a rearrangement of the boss battle music from Final Fantasy 4. After the battle, the classic FF victory fanfare can be heard, and during the post-battle conversation, the FF series’ prelude plays softly. Culex also gives out crystals, common symbols of the Final Fantasy series, when he’s defeated.

Culex was obviously intended to be a Final Fantasy-style boss, but he doesn’t appear in any other Final Fantasy game. However, it’s still nice to see him not only reappear in the remake, but even to be expanded on with a new transformation and a harder fight. Culex provides a nice little Easter egg for Final Fantasy fans, and a great challenge for Super Mario RPG completionists.