- Bocchi the Rock!: In Episode 11, one of Bocchi's Imagine Spots takes the form of a Stylistic Suck CG animation in which a t-posing render of her flies into a stack of blocks, punctuated by the sound of bowling pins being knocked over, parodying a similar scene from the PS4 trailer
for Undertale. - Pop Team Epic references the game on multiple occasions:
- One strip depicts Pipimi's neck growing while patting Popuko's head, parodying the pacifist method for beating the Lesser Dog fight; the anime adaptation of this bit also features Popuko uttering a sultry-sounding "oh yeeeeah" in the vein of Mettaton.
- One strip features Pipimi imitating Mettaton, complete with long legs and spotlights. Episode 7 of the anime adaptation takes the bit even further, outright reenacting the Mettaton fight as it appears in Undertale, with arms Flipping the Bird in place of legs. Toby Fox bemusedly reacted to the latter on Twitter, stating that he didn't expect it to be in the anime.
- Scott Pilgrim Takes Off: When Older Scott's trying to visualize to his younger self the impact that his separation with Ramona had, an image of a red pixel heart with a Flowey-like smile appears, only for said heart to gain a shocked expression with two little fangs in the mouth as tire tracks repeatedly strike it, referencing Flowey's death in the No Mercy Route. The sound effects during this scene even resemble the "hit" sound effect. The heart then bursts in a similar manner to the SOUL exploding.
- Being a Massive Multiplayer Crossover, CMC+ features Undyne, Asriel, Chara, and Sans (prior to V8) as playable characters. The Last Corridor and the Waterfall also appear as stages.
- In PreCure in a Nutshell, Sango Suzumura gets the parody name of Sans Suzumuzu.
- The Animated Music Video for "Hammerhead Shark Song" by Hirokazu Tanaka (under the stage name Chip Tanaka) is an extended homage to Undertale; Toby Fox even directed it with help from the Undertale and Deltarune staff.
- Shawn Wasabi's song "LEMONS" feature a sample of Sans' Voice Grunting near the end.
- In Dan Bull's song "The New Colossus", he says:
- Nearly as bad as writing in Comic Sans and Papyrus
- Sans appears as an Easter Egg inside the level "Goofy Goobers" in Around the Clock at Bikini Bottom. Interacting with a bottle with rainbow coloured hearts on it has him appear and chat with Patrick.
- Sans has a cameo in the epilogue of BoxxyQuest: The Gathering Storm, and gives you his autograph if talked to repeatedly. You can view the scene here. (The Undertale music was added by the video uploader.)
- Epic Battle Fantasy 5: Optional Boss Snowflake is a giant Undertale shout-out. From its monochrome, pixelated battle sprite, to its "dialogue" imitating Undertale's in-between turn messages, to even its death animation referencing Undertale's.
- One of Snowflake's quotes is a nod to the in-game dates:
* Snowflake is worried that you're taking this play-date a bit too seriously.- The name of the medal for beating Snowflake on Epic difficulty is called Determination.
- Snowflake's stat file is called "Underlegs" in the game's source code. The background used for its fight, meanwhile, is called "UNDERTALE".
- One of the notes in the first chapter of FAITH: The Unholy Trinity contains the line "But nobody came", which per the developer was an intentional reference due to them playing Undertale during the game's early development. The third Chapter contains graffiti of Gaster (or rather Mysteryman, who is widely considered to be him).
- A number of Crows Crows Crows tweets advertising The Stanley Parable: Ultra Deluxe nod to both Undertale and Deltarune, including a note on the official soundtrack jokingly clarifying that "But Nobody Came" isn't the Undertale song.
- In September 2019, Sans was added to Super Smash Bros. Ultimate as a Mii Fighter costume, along with a new remix of "Megalovania".
- In Completing the Mission from the Henry Stickmin Series:
- The "Little Nest Egg" path has a parody of Undertale's fights, with the same FIGHT, ACT, ITEM, and MERCY options.
- A stick figure version of Sans' face also briefly appears as a Freeze-Frame Bonus in the "Jewel Baron" route of the game.
- The console ports of La-Mulana 2 feature a shopkeeper named Burgerpantheus who, other than the name, backstory, and art style, is identical to Burgerpants in appearance and speech. He also carries a smiling gold sunflower similar to Flowey, and both will make their iconic facial expressions as you navigate the shop menu.
- Live A Live: In a case of recursive references, the penultimate song of the 25th anniversary concert was an Epic Rocking rendition of "Megalomania", referencing the rock in Undertale's version of "MEGALOVANIA". The band even incorporates the first few notes of the song into the finale.
- In Them's Fightin' Herds, Tianhuo has a palette based on Undyne while Shanty has one based on Toriel.
- Vine Realms includes a crab-themed parody of Sans in the form of Sands, a white, hoodie-clad crab with a blue eye who warns about "[having] a crab time." Sands even uses the same Voice Grunting as Sans.
- One of the secret Easter Eggs in Yandere Simulator turns Yandere-chan into Sans, complete with the blue hoodie, bone-white skin, black eyes (and the glowing blue left eye), and the ability to summon Gaster Blasters. In addition, one of the promotional videos depicts an Undertale-esque battle against Oka Ruto modeled after the Sans fight.
- In World of Warcraft, the Court of Stars dungeon in Legion has one boss who needs to have her lieutenants individually drawn away and killed, as trying to engage them all at once will result in them overwhelming the group. Trying to pull another lieutenant after all of them are killed will give the message "But nobody came."
- Cucumber Quest: On page 675, Peridot is shown wearing fluffy slippers that look like Toriel; Toby Fox even used a screencap of them as his Twitter profile pic for a while.
- In Homestuck (which Toby Fox had previously composed music for), a small piece of the final battle against Lord English takes the form of an Undertale-style fight.
- Sleepless Domain: The main character of the comic is named Undine — not after the Undertale characternote , but after the mythological water elemental that likely also served as Undyne's namesake. However, the Alt Text of a later page makes a joke about her retroactively similar name:Alt Text: Wait, like that video game fish person...?
- Strange School: To the Sans fight's dialogue:
- When talking to Iris: The fight's line "kids like you... Should be burning in hell.":Iris: ….But beings like him…..should be burning in hell.
You: …That sounds vaguely familiar— - The return of Meatlet Jr: The fight's line: "You're gonna have a bad time":Meatlet Jr: ...ur gonna hab a bath tim
- When
- Sans appears in this video of Destripando La Historia.
- In Professor Juice, R.O.S.I.E. (Robotic Operating System In Excellence) appears to be modeled after Mettaton EX. If that's not enough, the "Top 10 Robots in Gaming" list she's introduced in has Mettaton on it.
- Freshy Kanal:
- Frisk battles Chihiro in Part 1. Sans also shows up to rap against Yababa.
- Flowey battles Happy Appy in Part 3.
- Undyne battles Knuckles in Part 6.
- In the Real-Time Fandub of Sonic the Hedgehog (2006), when Eggman's glasses turn blue, he says "I am now Sans Undertale, go into my eyes!" and hums the first few bars of Megalovania.
- SiIvaGunner, being a video game-themed meme channel, is definitely no stranger to Undertale rips. In fact, its playlist is the biggest on the entire channel, other than the one for the King for Another Day Tournament, in which Papyrus appeared as a competitor.
- In Bluey, a plush dog version of Sans can be seen briefly in "The Sleepover" and "Mr Monkeyjocks".
