Vulkin is an enemy that the protagonist can encounter in Hotland.
As its name implies, Vulkin resembles a volcano, with the conical structure that is a common characteristic of volcanoes; lava can be seen leaking from its crown, and little puffs of smoke can be seen spewing out steadily. Vulkin usually has its eyes closed and a permanent blush. Due to its cheerful attitude, it is usually seen smiling.
Vulkin is a kind creature who, unfortunately for the protagonist, thinks its lava can heal people.
- Its "Thunder" attack is a cloud at the top center of the board, firing bolts at a wide angle toward the SOUL, separating more the farther they travel. A variation of this has the cloud move.
- This attack actually can speed you up if you get hit by it.
- Its "fire" attack is two columns at the right and left edges of the board, shooting fireballs toward the center; the fireballs go back to the column from which they were fired.
- For a Pacifist route, you can SPARE this monster by hugging or encouraging it. However, encouraging it will increase its attack, and hugging it will decrease the protagonist's defense.
- Criticizing it will discourage it from attacking altogether, which is useful when there is another monster.
- Thunder! Helpful speed up!!! [Neutral]
- Ah! I'll help! Healing magmas! [Neutral]
- Speed will help dodge!! [Neutral]
- You're hurt! I'll help!!! [Protagonist Low HP]
- Ahh... Not... helping? Okay... [Criticize]
- Trash... rump... Ahh... [Criticize twice]
- Ahh... [Neutral after being Criticized]
- Does not help... [Neutral after being Criticized]
- Oh! Ah! I'm helping!
- Ahh! Ahh! Does my best! [Encourage]
- Ahh! Tries the hardest! [Encourage]
- Works hard! Works hot! [Encourage]
- Ahh... so... LOVEY! [Hug]
- Feels so warm! [Hug]
- Hug...continue... [Hug]
- Mistakenly believes its lava can heal people. [Check]
- Vulkin strolls in. [Encounter]
- A strange parade blocks the path. [Encounter with another Vulkin]
- Tsunderplane attacks! Not because it's jealous Vulkin is paying attention to you! [Encounter with Tsunderplane]
- Vulkin is wiggling its weird rump. [Neutral]
- Vulkin is making coffee in its crater. [Neutral]
- Vulkin makes a smoke hoop and jumps through it. [Neutral]
- Vulkin stands in the corner. [Criticize]
- You tell Vulkin that its rump looks like a sack of trash. [Criticize twice]
- You tell Vulkin that its attacks are NOT helpful. [Criticize]
- Little streams of lava come from Vulkin's eyes. [Criticize twice]
- You tell Vulkin it's doing a great job. Its attacks become extreme... [Encourage]
- Vulkin parades around you proudly. [Encourage]
- You give Vulkin a hug. It warms your heart... | And your whole body! Ouch! Your DEFENSE dropped! [Hug]
- Vulkin's cheeks glow with a bright heat. [Hug]
- Vulkin assures you the plane turning tiny is, like, completely intentional. [When Tsunderplane is spared]
Vulkin's name comes from volcano and possibly Vulcan, the name of the Roman god of volcanoes and metalworking.
- There is a glitch where a Vulkin NPC will repeat the last message displayed, followed by the phrase: "smell the pain." 
- Vulkin may be mentioned during Mettaton's news report by the headline saying "TINY VOLCANO MONSTER DOES ITS BEST, RECEIVES TINY APPLAUSE."
- Vulkin shares its attack sound effect with Reaper Bird and Snowdrake's Mother.
|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