Moldbygg (/ˈmoʊldˌbɪg/) is an enemy the protagonist encounters in Waterfall.



It pretends to be a Moldsmal, but once approached or attacked, it reveals itself as Moldbygg. It can be identified before it transforms, as it is completely stationary and lacks animation in its Moldsmal form. Another way to tell if it is a Moldbygg is if it cannot be spared immediately.

In Battle

Appears With


  • Small Moldbyggs sprout from the bottom of the screen, shooting bullets at the protagonist's SOUL.
  • A reverse of Moldsmal's attack:
    • Eight bullets appear from the edges of the screen, converge on a point, then rise.


  • To spare it, use Unhug.
  • If Hug is used against Moldbygg, the SOUL's SPEED decreases for the battle. Touching Woshua afterward causes the latter to run away.


  • ... [Neutral]
  • Roar. [Neutral]
  • *Chaste wiggle* [Neutral]
  • Guoooh! [Neutral]
  • *Slime sounds* [Neutral]

Flavor Text


  • Moldsmal is very normal. [Neutral]
  • Moldsmal is having quiet time. [Neutral]
  • Moldsmal sits motionless. [Neutral]
  • Smells like a bait shop. [Neutral]
  • It's a slime mold...? [Check]
  • You lie immobile with Moldsmal. Suddenly...! [Imitate]
  • You wiggle your hips. Suddenly...! [Flirt]


  • One size greater than Moldaverage. [Check]
  • Moldbygg and Woshua appear. [Encounter with Woshua]
  • Moldbygg gyrates reservedly. [Neutral]
  • Smells like a bait shop. [Neutral]
  • Moldbygg mills about in the corner. [Neutral]
  • Moldbygg needs some distance. [Neutral]
  • You lie down. Moldbygg lies down too. Moldbygg understands life now. [Lie Down]
  • You hug Moldbygg. Gross slime covers you. Your SPEED decreased. [Hug]
  • You don't hug Moldbygg. It appreciates your respect of its boundaries. [Unhug]
  • Moldbygg seems comfortable with your presence. [When spare conditions are met]
  • Moldbygg has seen better days. [Low HP]


  • Moldbygg does not make an appearance in New Home to tell the story of Asriel Dreemurr.
  • Moldbygg is one of the monster species making up the Amalgamate named Lemon Bread; specifically, Lemon Bread is spared by un-hugging, an ACT adopted specifically from Moldbygg, and Lemon Bread appears to have Moldbygg's top-most tier segments as her teeth and several bumps from Moldbygg's lower tiers.
    • This is further illustrated in Lemon Bread's idle animation as she performs a "roaring" action, which might be a reference to one of Moldbygg's quotes.

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 • Mad Mew Mew
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
NPCs Snowdin • Waterfall • Hotland • MTT Resort
Other Characters Photoshop Flowey • Monster Kid • Annoying Dog • River Person • Eight Humans • Asriel Dreemurr
W. D. Gaster • Lost Souls