Top Ten Hardest Undertale Bosses


The Top Ten

1 Sans 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.

Look at his attacks! Unless you are a extreme boss, this boss is the hardest times about ten!

Lol whoever wrote ode to sans is hilarious

I gave up on him my 1st "geno side" (lol) route because he was so hard

Sans is definitely the hardest boss in Undertale. Difficult attacks, no saves, and no healing during the battle (cough, cough, Omega Flowey). Not only that, but Sans just looks plain evil.

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2 Omega Flowey

Looks like the hardest boss ever (tied with sans) because it's so powerful imagine a talking attracting deadly flies swinging cactus hands and shooting barrages of seeds all at once. Well good luck on that one because its pretty damn hard

I died like 15 times on this fight. The main things that got me are the finger guns and the FLIES UNAVOIDABLE anyway this boss proves that Flowey is the best character and nothing will ever beat him

Sans on hard mode is one hell of a boss, but Omega Flowey on Hard Mode is NUTS! X( I don't think anyone has beaten this boss on Hard Mode. - Doge4lifeGaming

Dear lord this is a true nightmare hands down the scariest thing or event in undertale he is also my favorite boss because it sticks out

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

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

What? This is not even that hard. Omega Flowey is WAY harder.

4 Asgore 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.

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


5 Undyne 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.
6 Undyne The Undying

Why is she at number 7 I have beat all these bosses but she has to be the 2nd hardest

This is one of the TRUE heroes of Genocide. Screw you Chara-possessed-Frisk.

Probably 2nd hardest honestly

How in gods name is she only number 7

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7 Mettaton 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!"


8 Muffet 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.

This boss was so hard to beat for me. Sure not as hard as undyne the undying and sans but this is harder than papyrus and undyne and mettaton EX!

9 Ruins Dummy

This is the hardest boss no doubt. The rock in the ruins might be tougher to beat though.

How do you beat this?

Sans trembles before the Ruins Dummy.

How dar u u nonce sans is hardest bos butt u get me mad becus u hateing becus you jelly of me litl kid

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10 Papyrus 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.

What the hell so easy beat him first try

The Contenders

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

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. - BrokenLightbulb


13 Mad Dummy

On him rn and it is so frustrating

14 Seven Human Souls

Give me a gun. - BrokenLightbulb

15 Napstablook Napstablook Napstablook is a secondary character from Toby Fox's 2016 RPG, Undertale. He is the cousin of Mettaton, who left him in order to become famous. Due to this, poor Blooky has crippling depression.

Can't kill a ghost

Don't cheer his dapperblook...I DARE YOU

16 Alphys NEO

She's not even in Undertale! - BrokenLightbulb

17 Mettaton NEO Mettaton NEO

SO EASY - coolgamert

THEN WHY IS HE HERE? - BrokenLightbulb

18 Lemon Bread

Very nasty first time.

Took me a few tries to beat this one

19 Annoying Dog Annoying Dog

Hardest boss ever! Who else agrees?

20 Knight Knight

Stupid annoying

Gives you hell

21 Jerry

HE DOESN'T EVEN ATTACK. - BrokenLightbulb

22 Whimsun

This guy should be last. - BrokenLightbulb



24 Temmie 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.

HOI AnD WeLcOmEz To... LiTeRaL hElL! - WarriorCatsHater

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