Monster Kid is a yellow, reptilian monster with no arms, a tail, and spikes on the back of their head. Having no arms and frequently running everywhere, they trip and fall often. They have markings under their eyes, speculated to be black eyes from falling. One of the markings is bigger than the other. They wear a yellow shirt with brown stripes.
Monster Kid looks up to Undyne as a role model. They are an innocent monster who assumes an energetic attitude that pervades most of their actions. They seem to be a bit naive, as well as a bit clumsy, as they trip frequently. They also use words like "c'mon," "dude," and "yo" frequently, usually considered childlike ways of interaction.
Despite the protagonist notably frightening Monster Kid during the Genocide Route (once they discover the protagonist's intentions), they stand up to the protagonist with an intense expression, ready to protect the Underground, trying to act like Undyne. Choosing to spare them and abort the route reverts them back to a more favorable opinion of the protagonist, showing a rather forgiving nature.
Monster Kid first meets the protagonist in Snowdin. They note how both of them are wearing striped shirts, so they both must be children. However, they do not seem to notice that the protagonist is a human child.
They later sneak out of Snowdin to explore Waterfall, looking for Undyne. They follow the protagonist, not knowing that the latter is a human whom Undyne is searching for, and they feel a little jealous of the attention that the protagonist receives.
Monster Kid eventually finds out that the protagonist is a human and reluctantly considers the protagonist an enemy. They try to say something mean to the human, in an attempt to become enemies, but feel bad for it and start to leave.
Just as Monster Kid leaves, they trip over an edge and hang from it while Undyne approaches. The protagonist must make a choice:
- Help them climb back up: Monster Kid defends the protagonist from Undyne, who backs off. They decide to remain friends with the protagonist and leave for home.
- Let them fall: Undyne dives down after Monster Kid to save them. She is badly hurt but refuses to rest. They then tell Undyne that she was right about the human, who just stood there waiting for them to fall. This response makes Monster Kid hate the protagonist and all humans.
- Run to Undyne: Undyne saves Monster Kid and is badly hurt. They tell Undyne that she was right about the human, who was too eager to fight her to bother saving them. This response also makes Monster Kid hate the protagonist and all humans.
- Run away from Undyne: Undyne helps Monster Kid up, who tells her that the protagonist was just going to get help from others.
Monster Kid is seen cheering the protagonist on to victory in the bottom-right corner of the battle screen as they face off against Flowey. In the epilogue, they can be found in Snowdin. If saved earlier, they say they do not think Undyne is that great anymore, and that they found themself a new idol, likely Papyrus. They are also seen during the credits, attending Toriel's school.
Despite being warned by Undyne that the protagonist has hurt a lot of people, Monster Kid approaches the protagonist in disbelief. The protagonist turns away, and as Monster Kid questions the protagonist about not answering them, the protagonist silently approaches them with a "weird expression," causing them to step back. Monster Kid begins to panic and wonders what they should do, and then stands up to the protagonist out of desperation, trying to act like Undyne, stating that if the protagonist wants to continue to hurt others, the protagonist would have to go through them. The protagonist then proactively engages battle with them, with the narration simply declaring "In my way." If the protagonist dies, reloads at the unnamed save before the bridge and returns to this location without the player closing the game, they simply attempt to trick the child into turning the other way before re-engaging. This encounter cannot be escaped.
- If the protagonist attacks Monster Kid, Undyne takes the fatal blow in their place. The kid escapes while harboring a shocked expression, and the protagonist fights Undyne the Undying. Monster Kid is not seen again for the rest of the game; it is assumed they evacuated with the others.
- If the protagonist spares Monster Kid, they say they knew the protagonist was not that bad and leave. This action aborts the Genocide Route, and the protagonist fights Undyne later in Waterfall normally.
A slowed down version of "Anticipation" plays during the battle. If the player resets after this cutscene (most likely by dying to Undyne the Undying), the scene is abbreviated: after Monster Kid approaches the protagonist, the protagonist tricks them into turning the other way, then re-engages battle.
|The following dropdown may contain spoilers.|
- Looks like free EXP. [Check]
- Monster Kid quivers anxiously. [Neutral]
- In my way. [Encounter]
- Monster Kid was designed by Magnolia Porter, creator of "Monster Pulse." She also designed Snowdrake, Ice Cap, Jerry, and helped design Gyftrot.
- The Pokémon Scraggy might be the inspiration for Monster Kid's design; both are small, yellow, bipedal lizard-like creatures with protruding teeth. While Scraggy may have arms, it has to use them perpetually to hold up its pelt, which is a lot like not having arms at all, just like Monster Kid.
- Monster Kid's assumption that the protagonist is a kid because of their striped shirt may be a reference to the MOTHER series, where in the main protagonists of each game are kids who wear striped shirts.
- If you look closely behind the Undying's head in the "The Undying" tarot card, you can see Monster Kid in the distance with a horrified look.
- ↑ "Maybe Undyne... isn't actually as cool as we thought. She's just kinda... mean. But YO!!! I just found out about someone WAYYY cooler!!! Nyeh heh heh!!!" - Monster Kid
|Main Characters||Flowey • Toriel • Sans • Papyrus • Undyne • Alphys • Mettaton • Asgore Dreemurr • Frisk • Chara|
|Ruins Enemies||Dummy • Froggit • Whimsun • Moldsmal • Loox • Vegetoid • Migosp • Napstablook|
|Snowdin Enemies|| Snowdrake • Chilldrake • Ice Cap • Gyftrot • Doggo|
Dogamy and Dogaressa • Lesser Dog • Greater Dog • Jerry • Glyde
|Waterfall Enemies||Aaron • Moldbygg • Woshua • Temmie • Mad Dummy • Shyren|
|Hotland Enemies||Vulkin • Tsunderplane • Pyrope • Muffet • Royal Guards • So Sorry|
|CORE Enemies||Final Froggit • Whimsalot • Astigmatism • Madjick • Knight Knight|
|Amalgamates||Memoryhead • Endogeny • Reaper Bird • Lemon Bread • Snowdrake's Mother|
|Hard Mode-only enemies||Parsnik • Moldessa • Migospel|
|Vendors||Nice Cream Guy • Snowdin Shopkeeper • Gerson • Tem Shop • Bratty and Catty • Burgerpants|
|Other Characters|| NPCs • Monster Kid • Annoying Dog • River Person • Eight Humans • Asriel Dreemurr|
W. D. Gaster • Lost Souls