Hardest Bosses In Undertale

Summary

• Undertale features some of the most challenging boss fights in gaming, such as Asgore Dreemurr and Undyne the Undying.
• Bosses like Mettaton EX and Mad Mew Mew provide hard battles with extremely creative mechanics.
• The final boss of the Genocide Route, Sans, is considered one of the hardest video game bosses ever due to his powerful attacks and challenging mechanics.

Since 2015, Undertale has been conquering the hearts of gamers all around the world with its quirky and lovable characters, mind-blowing story, great satire of the RPG genre, and creative mechanics. This last part is especially important because its unique gameplay has allowed Toby Fox to create some of the best and most brilliant boss fights in the gaming industry.

While some of the boss encounters in this beloved indie game are known to be funny and/or emotional, many others are infamous for being extremely challenging for the player, especially those that take place during the Genocide Route. Undertale features a good number of hard bosses, but the following are the toughest ones in the entire adventure.

8

Photoshop Flowey

A Creepy Giant Boss With A Collection Of Confusing Attacks

Players who have managed to face the final boss of the Neutral Route, Photoshop Flowey, will be immediately disturbed by his photorealistic design and his unsettling laugh. And to make things even worse, the fight itself is also quite tough, especially for newcomers.

Photoshop Flowey’s attacks are surprisingly quick and very hard to avoid. On top of that, the constant swapping of the battlefield, combined with his disturbing design and the chaotic music, can make this battle very disorienting for the player. Fortunately, this challenge ends up being completely worth it because the conclusion of this boss fight is one of the most emotionally satisfying moments in the entire game.

7

Asriel Dreemurr

The True Final Boss Of The Game Presents A Formidable Challenge

Players who were able to play through the entire True Pacifist Route will discover that the real final boss of Undertale is actually Asriel Dreemurr, a tragic character that had a major role in the narrative. This all means that he’s the final challenge in the entire game, so it makes sense that he’s very hard to defeat.

Asriel attacks the player with a relentless array of powerful techniques that he almost doesn’t telegraph, like giant star-shaped meteors, pillars of electricity, and finger bullets that he can shoot at extreme velocity. At the end of the day, however, Asriel’s battle is not as challenging as others in the game because it also features a lot of emotional story beats that would be completely undermined if the player got frustrated trying to defeat him.

6

Mettaton EX

Mettaton is, without a doubt, one of the most bizarre yet beloved characters in all of Undertale, so it is no surprise that he’s the star of one of the most creative but challenging battles in the entire game. Since he’s the biggest (and only) television star in the Underground, the boss fight against Mettaton EX revolves entirely around the medium of television.

This means two things: To win, the player must keep fighting him while slowly raising the TV ratings, and that Mettaton EX can utilize many confusing abilities that fit the theme, like changing the size of the player’s screen and suddenly rewinding his attacks. This results in a surprisingly tough but satisfying battle with a lovable character and catchy background music. Sadly, the same can’t be said about Mettaton’s counterpart from the Genocide Route, Mettaton NEO, who always dies in one hit.

5

Mad Mew Mew

A New Boss That Was Made Specifically For The Nintendo Switch

Mad Mew Mew is a brand-new optional boss that was added to the Nintendo Switch version of Undertale. After defeating Mettaton EX, players can face her in the Dog Shrine, and, curiously enough, her battle is as entertaining as it is challenging. Her fight is themed after the Nintendo Switch, with the player’s heart being divided into two halves (one blue and one red) that can be controlled with each of the Joy-Con’s analog sticks.

This surprise mechanic already makes the fight against Mad Mew Mew a lot tougher, but it gets even worse when she begins using fast and disorienting attacks in which the player is supposed to quickly match each half of the heart with their respective color. On top of all that, she is also able to change the shape of the player’s screen to turn it into a small rectangle or an octagon, heavily restricting the space they can move around in the process.

4

Muffet

An Adorable Boss With An Intense Platforming Challenge

Even though many fans consider her a mini-boss, there’s no denying that Muffet is one of the most memorable characters in the entire game. Like most other important bosses, this lovely spider-themed baker has her distinct gimmick, as she can change the color of the player’s heart and force them to move it exclusively between three straight lines.

This small change completely changes the difficulty of the encounter, as limiting the heart’s movement makes it way harder for the player to move around and avoid Muffet’s attacks. She starts relatively easily, by using various pastries as projectiles, but she quickly ramps up the challenge by moving around the screen and by summoning her pet spider, which the player has to avoid by rapidly jumping in-between the purple lines. This is a hectic battle, but it’s also an entertaining one, which has helped cement Muffet as a major fan favorite.

3

Asgore Dreemurr

A Tragic Character That Put Up A Great Fight

At the very end of the Neutral Route, the player has to fight Asgore Dreemurr, the King of the Underground, Toriel’s wife and Asriel’s father. Much to the shock of the player, he immediately destroys the Mercy Button, meaning that he’s one of the very few bosses in the game that is completely mandatory to attack. This small element is enough to turn this into a tragic battle, a sentiment that is elevated by the beautiful background music.

Just like his wife and son, Asgore fights by summoning an overwhelming number of fireballs that are extremely tricky to avoid, and he’ll cover the screen with projectiles in an instant, like if he was a boss from a bullet hell shoot ’em up game. Additionally, he can also attack with his trident by turning it orange or light blue, meaning that the player must pay close attention and either stay still or move around in an instant, depending on its color. Despite the extreme challenge, this is still one of the best and most emotional encounters in the entire game.

2

Undyne The Undying

A Relentless Battle Against A Hero That Intentionally Punishes The Player

As the leader of the Underground’s Royal Guard, it’s no surprise that the Neutral Route fight against Undyne is quite tough in and of itself. But her counterpart from the Genocide Route, better known as Undyne the Undying, is even harder, and, as a result, it’s now infamous for being one of the biggest challenges in all of Undertale.

The main gimmick of Undyne’s battle is Shield Mode, which protects the player’s heart with a shield but also completely cancels its movement. This means that the player will have to pay constant attention to their surroundings and swiftly switch directions to block Undyne’s rapid-fire arrow attacks. But that’s not all, because she can also revert the heart to its regular Red Mode and keep relentlessly attacking with her spear-shaped projectiles. Of course, the challenging nature of this fight shouldn’t be a surprise, seeing as it is exclusive to the Genocide Route, which repeatedly punishes the player for their malicious actions.

1

Sans

The Most Famous Undertale Boss Is Also The Hardest One

Sans is, without a doubt, the most popular and iconic character in Undertale, not only due to his silly design and comedic antics but also because of the incredible battle he stars in. After all, he’s the final boss of the infamous Genocide Route, which means that he’s both its final challenge and its final form of punishment.

This fight is only fit for those who have completely mastered the mechanics of the game, and it shows: Sans can attack the player by summoning gigantic bones, shooting light-speed laser beams, changing their screen in the blink of an eye, and even controlling the gravity by turning their heart into Blue Mode. The main theme of this fight is patience, as the player has to avoid most of his attacks and receive as little damage as possible, only to attack and kill him with one hit at the very end. This, of course, is easier said than done, and there’s a reason why Sans is still highly regarded as one of the hardest video game bosses ever created.