Characters
This character calls himself "your best friend".
Flowey.
This item skips the entire Muffet fight for a mere 7 gold.
Spider Donut.
This character says the line "NYEH HEH HEH!"
The Great Papyrus.
This enemy resembles a certain contributor (who is NOT Toby Fox) to UNDERTALE.
Temmie!
He is the man who speaks in hands.
W. D. Gaster.
This character believes anime is real.
Undyne.
This armor is the most expensive item in the game.
Temmie Armor.
This character says the line "This world needs stars more than it needs corpses!"
Mettaton.
This enemy gives you negative EXP for killing them.
Napstablook! You technically don't "kill" them, but you can lower their health bar.
Define DETERMINATION.
Determination is a substance that allows souls to persist after death.
This (these) UNDERTALE character(s) are a trans allegory.
Mettaton and Mad Mew Mew.
DOUBLE POINTS: The Lion NPC.
This weapon does the most damage in the Neutral/Pacifist Routes.
Empty Gun. Although the Worn Dagger has a higher attack value, due to the way critical hits are calculated in UNDERTALE the Empty Gun's six different attack bars when all hit properly give it an insane amount of damage.
This character says the line "Dishes a very bad joke."
sans.
This UNDERTALE enemy has the lowest defense.
Mettaton NEO.
This DELTARUNE character was hinted towards in UNDERTALE.
Susie. In a FUN event, an NPC talks about someone called "Suzy", who is about Frisk's age and would be friends with them.
This character is called "Mike Wazowski" in the files.
Loox.
This item has a game-breaking bug used extensively in the speedrun.
The Punch Card.
This character says the line "King ASGORE will let us go."
Moldsmal.
This enemy was designed by OMOCAT, creator of Omori.
Woshua.
The "Soul Trait" of the red soul color.
Unknown, there is no canon soul trait given to the red soul.
This Hotland NPC has an unforgettable name.
Heats Flamesman.
The Cinnamon-Butterscotch Pie heals ALL of the player's HP. This item also heals all HP.
Dog Salad OR Bad Memory.
This character says "'Friendship' is just a hot person's way of making you their slave."
Burgerpants.
In Hard Mode, some RUINS enemies get replaced by enemies seen later in the game (Froggit with Final Froggit, Whimsun with Whimsalot, etc). Moldsmal gets replaced by this enemy.
Moldessa. Moldsbygg does not appear in Hard Mode.
In the FUN value 66 event, a hallway is added after the crystal cheese save room. This hallway can spawn a door with a strange NPC in it. This NPC is named...
Mysteryman.