Top Ten Hardest Undertale Bosses

The Top Ten

1 Sans Sans or Sans the Skeleton is a character in the 2015 RPG Undertale created by Toby Fox. He is a lazy, pun-loving skeleton who is a supporting protagonist in the "pacifist" and "neutral" routes of Undertale, and a heroic antagonist/final boss of the "genocide" route. He is known for his incredibly difficult more.

I think sans is the hardest because when he sends you through those attacks and it blacks out so you have to remember what the attack was.

I haven't fought him, but I've seen videos, and he is EXTREMELY HARD!

The battle was painful for my mental health. I swear I could hear gaster blasters in my sleep until I beat him.

Though you don't have to fight sans, he is extremely hard. Everyone should know this.

2 Omega Flowey

Basically the final boss of just shapes and beats but 2x as hard. His attacks are fast and to the point.

Although his battle does SAVE, no amount of skill can let you NOT DIE on this guy. To be fair, I haven't attempted the genocide route, so I haven't battled Undyne the Undying or Sans, but he is much harder than Asriel, as his battle SAVES even more.

Other boses are challenging but you can memorize there attack patterns over many repeats you can do that with flowey sure but I don't have the reflexes. I remember coming out of the asgore fight and found him one of the easiest bosses but then flowey came and killed me almost instantly over and over I haven't fought sans or Asriel but I can't see them coming close to the difficulty of flow since I can't fight him for more then 20 seconds

He’s not too hard to me asgore was way harder like I only died once in this fight

By Derpo

3 Asriel Dreemurr Asriel Dreemurr is a character from the 2015 game "Undertale". He was created by Toby Fox. more.

asriel the god of hyper death is very hard but thr attacks are easier basicly like a normal asgore

Only boss I died to. (not counting sans or omega flowey.) LIKE, COME ON. IN HIS TRUE FORM, HIS ATTACKS ARE INSANE. But the sad part is... when... he begs for you to let him win. Then he does that INSANE attacks where you barely survive.

Didn't want to vote for this, but you cannot die during this fight. Froggit is easier

How is this fight hard? You can't even die in it!

4 Undyne The Undying

I spent almost 2 entire days trying to kill her. I was so happy when I could finally beat her.

hard please I wanna cry I'm gonna make her into fish fingers soon if she keeps this up

I actually beat Sans under TWO tries and I beat Undyne the Undying under SEVEN tries

Undyne is incredibly hard. She is surpassed only by a fat-*** skeleton.

5 Asgore Asgore Dreemurr is a boss monster and the king of the monsters in the 2015 RPG Undertale made by Toby Fox. Asgore is the portrayed main antagonist who plans to acquire seven human souls and use their power to break the barrier that seals the monsters underground . Aspects of his character are hinted more.

Asgore took me a while to beat but after that, I got his attacks in my head easier.

Good god. On my first playthrough, I got through Undyne in 2 tries, The Dummy in 1, and Muffet in 4. Asgore took me 27. Asgore is HARD.

Asgore is like an exam you didn't study for.

Actually, the fight is not that hard of you eat the pie.

6 Undyne Undyne is a main character in Toby Fox's 2016 RPG, Undertale. She is the heroic fishlike captain of the Royal Guard, who takes it upon herself to protect the monsters of the Underground. Her name is derived from the word "Undine", and is a pun on the word "Undying". Her most loved monsters are her mentor, more.

How do people get past this sometimes first try although sans is hard I survive longer against him then undyne

Undyne is just hard no matter if its genocide undyne or regular

This is way harder than any of the above apart from sans.

its hard to get past undyne

7 Mettaton Mettaton is a character in the popular 2015 RPG game, Undertale. He is a robot with a soul built by Dr. Alphys, and is the sole television star of the underground. Mettaton is a popular character in the fanbase. His notable features include his legs, and his catchphrase "OH YESSSS!"

on the essay question, I just said, "lol he sucks" and then he said, "perfect! you get a gold star!".

Only person I died to in pacifist run through (and that was my first time through)

Along with Undyne, the one of three bosses I died two on my last playthrough.

The background music is good but he is challenging as hell!

8 Muffet Muffet is a character from the game Undertale. She appears in a region called Hotland, selling pastries to raise money to rent a heated limo to help the spider clan from the Ruins (who are also raising a bake sale) reunite with the one in Hotland because the spiders can't cross Snowdin.

Unless you have a Spider Donut and/or Spider Cider from the Ruins, Muffet's pet is super good at DESTROYING you.

Muffet got my vote. The way her attacks come at you. Eat a spider donut in front of her to skip the battle or if you already bought a spider donut in the ruins, in the dinner phase a spider will bring up a note and the battle will end. Struggle or pay to slow her attacks. Took me many tries.

I eventually just gave up and started selling a bunch of crap to temmy bc I did not want to put up with her crap.

Muffet is actually pretty easy to beat IF you saved the spider donut or spider cider. I had it and ate it in front of her. But if you don't have one, you have to spare her 17 times, I think.

9 Ruins Dummy

Really hard.
Impossible, almost.
All of those attacks are just straight CRAZY!

Ok I did not vote because it's hard (we cannot be sure 'bout his gender) but because he is so easy. JUST. LET. THE. BULLETS. RUN. INTO. HIM.

Everything was a piece of cake until this fight. Took me SO LONG to get past it. Also, beware it's last attack. Those bullets are insta-kills!
What the heck, Toby!
And this site! How is this number 6?! It's worse than Sans!

After I completed my Genocide route, I was feeling like I could defeat anything. And then I remembered the Dummy in the Ruins. GOD, I had to hack the game to get past him. All monsters bow before the dummy.

10 Papyrus Papyrus is a character from the 2015 game Undertale, made by Toby Fox. He is the Younger brother of Sans the skeleton, royal guard in training, and a sentry in the town of Snowdin. Opposite to his brother, papyrus is active, loud, and full of himself; but in an endearing way. Papyrus means to become more.

Papyrus is pretty easy if you ask him on a date then he gets really distracted

No...Papyrus is easy...Plus you can skip his battle and befriend him if you die three times instead..

He was only threatening in Disbelief. In regular Undertale, he is a cake walk.

I don't think you can actually die against him - it's impossible.

The Contenders

11 Toriel Toriel is a main character in Toby Fox's 2016 RPG, Undertale. She is an amazing blend of goat and mother.

Technically, you can't die in this fight, but just TRY to not get to 2 HP when you are on pacifist. It's freaking impossible!

Strangely I defeated Photoshop Flowey in three tries but on Tori on my second playthrough this was hard.

But toriel's attacks avoid you

how. do. you. not. die. 10. times.

12 Mad Dummy

He took me around 4 or 5 tries to beat, so not really that hard...

I don't need friends! I've got knives!

I'm out of knives.

Attacks get me sometimes(especially on dummy bot final).

Really frustrated me on my first playthrough.

13 Froggit

Hardest boss in game. don't even tell me anything else you fool!

Froggit didn't understand what you said, but was flattered anyways.

Hardcore, I was stuck on them for a very long time. He wouldn't turn yellow, and I was so confused

Please tell me you are joking.

14 Disbelief Papyrus

I've seen videos, and tried fighting him myself...EXTREMELY HARD.

Bones orange bones blue bones orange Gaster blasts sans and Undyne the undying

This is literally the easiest boss since this character doesn’t even exist

By Derpo

Disbelief papyrus is very hard on phase 3 because he summons sans and undyne because he’s mad I think


The blasts lol

I mean... I like his lore.


yes, he SHOULD be 1st!

16 Ultra Sans

He is awesome and he is so hard if you think sans is hard try this dude

Lasers hands and laser moever

He kills you if you don’t have the artifact

17 Annoying Dog

This is actually mist likely the strongest character in the game, he created this world (undertake), so he can easily destroy it all, he could kill you (Frisk),Sans, Papyrus, Undyne, just with a single button

By Derpo

Hardest boss ever! Who else agrees?

Cute picture

Is it even a boss

18 Chara Chara is a character in the game Undertale by Toby "Radiation" Fox who is one of the seven people to fall to the Underground prior to the fall of the player character. Her name can be changed by the player and will be assumed as the player character, until the Pacifist Route when Asriel asks for the more.

Legitimately can't get rid of her in your files (unless you do some complex "hacking" stuff) so yeah

Oh jeez this has to be the hardest. Most people don't know how to battle Chara. Look it up on Youtube and watch. Most are fake actually or fan-made. Trust me, harder than Sans.

So hard can't beat it

Chara is a god. She can kill you so quick.

19 Alphys NEO

Alphys have lasers Gaster blasts fast forward play raced rewind and
light nig

She's not even in Undertale!

The attacks cool but difficult

Harder than any boss combine

20 Temmie Temmie is minor character from the 2015 game Undertale made by Toby Fox. Made in the likeness of her artist, Temmie Chang, in appearance and character. Both a character and a species of monster, temmies are defined by their mix of cat and dog features, as well as their broken English. Their hidden village more.

TEMMIE for the win

So hard.

Temmie for the win

HOi wElCOme tO...

Da tems to hard to beats

21 So Sorry

I feel so sorry for so sorry. He doesn't mean to fight you. He just ran into you and started the fight

Harder then muffet, undyne, papyrus and maybe asgore but not mettaton

This is a secret boss, but it's hard, I can say it's the sixth hardest boss after ASGORE

Harder than undyne, muffet and maybe mettaton

22 Flower Flowey is a flower in the RPG Undertale. He is the first character you meet, and also your best friend.

He almost instakills you with a single hit, manipulates you and makes it impossible to escape. By sheer luck they make a mistake and use a super heal on you which they could use on themselves easily! Also don't even have the option to act! They just have one attack and they go first instead of you plus they will remember everything!

This dude sssoo easy

Hell to the naaw

he's pretty easy JUST.KILL.HIM

23 Frisk

Frisk is easy to beat. Just get her soul to run into something harmful.

Greatest character

Frisk is easily the hardest boss in the entire game, you can’t even hit them. Why did Toby Fox put an unbeatable boss in the game smh

24 Dusttale Sans

Seen videos and don't even wanna try cause of how he is

;-; I don't know why did I vote for him

This dood is hecking insane, like bro.

... he has gone mentelly insane!

25 Greater Dog
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