Foolish. Foolish! FOOLISH!
~ Mad Dummy
I'll defeat you and take your SOUL! I'll use your SOUL to cross the barrier! I'll stand in the window of a fancy store! THEN EVERYTHING I WANT WILL BE MINE! Huh? Yeah, I guess that'll avenge my cousin. What was their name again...? Whatever. Whatever! WHATEVER!
~ Mad Dummy during their fight.
... That's it!!! YOU!!! Human!!! Fight with me!!! COMBAT!! BLOODLUST!! DESTRUCTION!! It's the perfect emotional cocktail… To fuse with my new body, mew~ And, with my new special ability… This battle will be TRULY INTERESTING!!!
~ Mad Mew Mew

Mad Dummy (also known as Mad Mew Mew in the Switch version) is a minor antagonist and mini-boss in the indie-RPG game, Undertale. They are a ghost monster that lives inside a dummy in the Garbage Dump and the other dummy's cousin. They try to kill the protagonist to avenge their cousin, regardless of what their actions are.


The Mad Dummy seems to be somewhat psychotic, wanting to avenge their cousin even if the protagonist does nothing to them. They seem to hate to feel powerless since they felt disarmed when it's dummies don't kill the protagonist quickly. They also often repeat themselves at least three times and they maniacally laugh often.

Despite their psychotic nature, they seem to be calm and collected at times given that they can cooperate with some other people and they do leave Frisk alone after Napstablook interrupts their battle and they serve as Undyne's punching bag for training outside of her home.

When the Mad Dummy turns into Glad Dummy on the Genocide Route, they become so angry that they became corporeal with their dummy, making them happy and thankful to Frisk, so if anything, the Mad Dummy just needed to let off some steam.

They also seem to care about their cousin, but they might be a little overprotective considering that they still attack the protagonist even if they do not do anything to them.


Pacifist/Neutral Routes

When the protagonist is about to leave the dump in Waterfall, the Mad Dummy encounters them. They reveal that their cousin was possessing the training dummy from the beginning of the game. No matter how the player interacted with the dummy earlier in the game, the Mad Dummy is enranged and attacks the player.

They intended on stealing their soul and after failing to kill the protagonist, the battle is interrupted by Napstablook, ending the battle and the Dummy leaves.

They are later found outside of Undyne's house. If the True Pacifist Route is completed, the Dummy apologizes for it's actions by calling itself a dummy.

Genocide Route

When encountering Mad Dummy in the Genocide Route, the amount of hatred directed towards the protagonist's actions allows them to "fuse with their body," fulfilling their lifelong wish. As a reward, they are willing to spare the protagonist as soon as combat begins. Unfortunately for the newly-renamed Glad Dummy, they are now vulnerable to physical attacks. The player then has the option to spare or kill the Dummy. If they kill them, the Genocide Route continues, if they spare them, the Genocide Route is aborted.

Nintendo Switch Version

In the Nintendo Switch version of Undertale, after the battle with the Dummy, they find and possess a Mew Mew doll in Sans and Papyrus' house and attempts to fuse with it. However, they fail.

After defeating Mettaton EX, the protagonist can enter the doors to Mew Mew. They can either fight or touch the doll. If the doll is touched a certain amount of times, a fight can start.

After their fight, they can appear outside of Undyne's house in the True Pacifist Route, and in the credits, Mew Mew replaces the Dummy.



Mad Mew Mew



  • It is implied that the Mad Dummy is also one of Napstablook and Mettaton's cousin given an entry in one of the diaries found in Mettaton's home.
  • It is implied that the Mew Mew doll they found was Alphys' since she is a fan of Mew Mew and they claim they found it in a "sciencey place."
  • If you include the Switch version of Undertale, Muffet and Mad Mew Mew are the only two mini-bosses with their own SOUL Modes.
  • Despite caring for their cousin, they don't seem to know their name.


           Undertale Logo/Deltarune Logo Villains

Frisk | Monsters (Flowey, Asgore Dreemurr, Muffet & Amalgamates) | Mettaton | Mad Dummy | Chara | The Anomaly

Chapter 1:
Darkners (King, Lancer, Rouxls Kaard, K. Round & Jevil) | Monsters (Susie, Asgore Dreemurr & Asriel Dreemurr) | The Knight

Community content is available under CC-BY-SA unless otherwise noted.