The true name of the Snowgrave route, as claimed by Toby
What is the Weird Route
This glitch in a secret boss fight was, instead of being patched, implemented into the game.
What is the Infinite Big Shot glitch (found in NEO Spamton's battle)
The name given to a motif found in multiple songs from the OST, including THE WORLD REVOLVING, BIG SHOT, Hammer of Justice, and more..
What is the Freedom motif
Who is Jevil
A theory that is widely accepted as canon claims that the Knight is a member of this family.
What is the Holiday family
The Forgotten Man or the Man Behind The Tree will give you this item when interacted with.
What is Egg
This event will happen if you play the first four notes to MEGALOVANIA on the organ in Chapter 4.
What is the Annoying Dog Running Over You With Its Car
This recurring theme contains Lancer's leitmotif.
What is Roulxs Kaard's theme/What is "It's Pronounced 'Rules'"
This fight is the only fight in Deltarune where you are guaranteed a no hit fight.
What is Dummy/Ralsei's dummy
The theory that Kris dislikes Ralsei based on an item in Chapter 2
What is the Tea Theory
This line in the prophecy finishes in these 5 words: "The second hero. The girl, with ___"
What is "hope crossed on her heart"
On the official Fangamer website, these two plushes are only available for preorder together.
What are the Tenna and Spamton plushes
This song from Undertale is strikingly similar to the last song played during gameplay in Chapter 4, which plays while Sans and Toriel dance.
What is Dummy!/Ghost Fight
What is Pipis
This theory claims that, in the prophecy, two girls are mentioned instead of one, and that Noelle will actually be the one sacrificed, not Susie. Hint: this theory is more centered around the fact that Susie was prophesied to be the antagonist)
What is Dark Axe Theory
This is the name of a sprite that is only seen in-game a few times, with eyes colored notably pink and yellow.
What is IMAGE_FRIEND/Friend
These two Deltarune characters, along with the Undertale bosses Asgore and Asriel, are the only ones that have the ability to alter your fight menu.
Who are Gerson and Roulxs Kaard
There are 8 songs in the OST that contain this leitmotif. Hint: one of these songs is Raise Up Your Bat.
What is the Jigsaw Joe fight
A pre-Chapter 3 theory that has since been disproven, predicting the theme for each chapter's boss would be similar to that of Chapter 1.
What is Chess Theory
References to these two characters can be found in a trashheap in the game Undertale.
Who are Spamton and Tenna
This healing item changes from 60HP to 100HP if a specific dialogue option is selected in Chapter 4. However, this change is internal and therefore unviewable in-game.
What is Ralsei Tea
d.ogg, a song file played at 0.14% of its original speed when doing the Snowgrave route, is the background for this song in Chapter 3 (at its original speed, of course).
What is Raise Up Your Bat
Kris will do this in the fight against the Roaring Knight if you have the Shadow Mantle and no-hit the boss.
What is cough
Which theory with multiple names (both will count) has a huge amount of writing and in depth explanation of meta writing to theorize that the Knight creates Dark Fountains for the player to seal, allowing the player to play with their world and then have it erased.
What is Oblivion Theory/Pile of Snow Theory/Knight is the Vessel Theory