Undertale has become a cult classic since developer Toby Fox's release of the 2D RPG in 2015. Its score, also composed by Fox, is iconic in the video game scene, but its unique bosses are also a talking point.
Undertale: 10 Hardest Boss Fights, Ranked
Some of Undertale's boss fights are quite challenging — these are the hardest of them.From iconic enemies, such as Greater Dog and Papyrus, to the nightmarish creations of Flowey and Muffet, Undertale bosses are some of the most memorable within indie gaming. Here's every boss in the game ranked based on their difficulty and memorability.
23 Mettaton NEO
The Genocide Route allows players to encounter Mettaton NEO, the evolved form of robot, Mettaton, who rocks a distinct look in the game.
With no attacks to launch your way, Mettaton NEO is perhaps the easiest boss to beat, as he can be killed in one hit, and is therefore fairly forgettable.
22 Glyde
Glyde is the first hidden monster on this list who can only be seen if the player enters the Mysterious Door in Snowdin for over two minutes.
Even though Glyde’s stealth is admirable, players often never encounter this monster during their playthrough, and time spent with the creature isn’t as impactful as many of the other bosses.
21 Shyren
Shyren is a mermaid-like monster that appears in Waterfall and battles with her back turned away from the protagonist because she’s ashamed of her appearance.
Despite sympathizing with her self-esteem issues, Shyren is a rather forgettable boss who is easily surpassed by many other foes on this list.
20 Royal Guards
Even though several bosses in this ranking serve in the Royal Guard, the miniboss duo of Hotland pose little to no threat during gameplay and carry basic designs.
However, the first guard’s romantic feelings for the second in command are a unique arc for these foes, which lands it slightly higher than some of the more forgettable encounters.
19 Dogi
Dogamy and Dogaressa are known together as Dogi and earn a slightly higher place in the lower ranks simply because of their undying love for each other.
With no real threat being produced by the couple, players can easily pass these minibosses in Snowdin Forest without concern.
18 Doggo
Another miniboss of Snowdin Forest, Doggo, is a member of the Royal Guard that uses blue attacks and has a serious case of bombastic side-eye.
If you choose to spare him, you’ll be rewarded with his second appearance as an NPC in Grillby’s, but that’s about all this boss has to offer.
17 Mad Mew Mew
This human-cat hybrid with a penchant for fashion appears in different locations depending on what console you play on. She appears in Papyrus and Sans’ House on the Nintendo Switch and behind the poker table on Xbox consoles.
She can only be encountered after battling Mettaton, and after she unleashes her Mews, this adversary’s vanilla encounter keeps her in the lower ranks.
16 So Sorry
This shy-looking kangaroo is a hidden miniboss of the Art Club Room and was added to Undertale during the game’s crowdfunded Kickstarter campaign.
His tail whips and paper tosses can be a challenge for players who have to practice their dodging game, but this boss doesn’t match the intensity of higher-ranked entries.
15 Lesser Dog
Carrying the good-boy demeanor is Lesser Dog from Snowdin Forest, sharing the same grounds as Doggo and Greater Dog.
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Get groovy with the skeleton boy... if you're in Japan.Wielding a sword and shield gives this boss one of the more pleasing designs of the game, but his blue spear and Annoying Dogs are fairly easy to get past.
14 Greater Dog
Greater Dog, the miniboss of Snowdin Forest, earns a slightly higher spot than his comrade, Lesser Dog, because he is another instantly recognizable mascot of Undertale.
Its spear sporting a dog's face can be tricky to dodge particularly on Pacifist, but otherwise, he’s a fairly harmless brute to be admired.
13 Napstablook
The ghost, Napstablook, is a musician that dwells in Waterfall and is one of the game’s minibosses that offers no real threat.
Even though he can be passed rather quickly, the character’s theme is a catchy tune, and he earns a higher place on the list for being one of the better characters in the game.
12 Mettaton
Mettaton is the final boss of the CORE and serves as a lethal robotic weapon built by Alphys with a high human kill count.
Existing as the only television star of the Underground, Mettaton doesn’t pose much of a threat to players, unless dodging is not your strong suit.
11 Toriel
Flaunting a terrifying goat-like appearance, Asgore’s ex-wife, Toriel, is the first boss of the game standing guard in the Ruins.
Despite her attacks being relatively easy to dodge, the decision to spare Toriel or not brings a sweep of emotion into the first big fight and earns her a middle-tier ranking.
10 Mad Dummy
Mad Dummy, a ghost inhabiting a dummy, is perhaps the most divisive boss on this list, as some find it incredibly easy to beat and others struggle to surpass the bullet play.
Located at the Garbage Dump in Waterfall, this miniboss looks relatively harmless, but its deceiving appearance makes this a more memorable encounter on this list.
9 Muffet
The miniboss of Hotland has one of the more terrifying designs in the game, and she gets furious if you don’t buy her extortionate goods.
If you’re aided by Spider Food to beat Muffet, then there is no real challenge ahead, but without food is where this boss can get tricky.
8 Amalgamates
This mutated boss is made up of Memoryhead, Endogeny, Reaper Bird, and more, with some being relatively easy to beat and others offering a greater fight.
Player experiences with this experiment gone wrong are subjective, but their backstory is one of the more interesting origins which earns them a higher place on this list.
7 Papyrus
The brother of Sans - who also makes an appearance on this list - is one of the more recognizable bosses in Undertale and puts up a fair fight in his plight to join the Royal Guard.
The last boss of Snowdin exists beside some of the more difficult bosses of the game. Dodging bones and getting caught in a restart time loop keeps this boss memorable on our ranking.
6 Mettaton EX
Mettaton EX is the gnarly evolution of Mettaton on the Neutral or True Pacifist Route, rocking a new-and-improved humanoid form with an emo-styled haircut.
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5 Asgore Dreemurr
Ruler of the Underground, Asgore Dreemurr looks like a cross between Dracula and a Viking and serves as the second-last boss on the Neutral Route.
Healing items are a crucial addition to your inventory when battling Asgore, but his son, Asriel, poses a bigger threat which lands him a lower ranking.
4 Photoshop Flowey
Photoshop Flowey, or Omega Flowey, is the monster that appears after devouring six SOULs on the Neutral Route and stands as the final boss.
Experiences with this enemy vary, with some saying he is the hardest of the game and others sailing through because of low damage taken. Either way, his nightmarish design earns a higher ranking.
