There is a monster encounter where your adversary is a cat-like creature. Like all monster encounters in this game, it is possible (but not required or recommended) to kill her. Additionally, there is an anthropomorphic cat creature who acts as a shopkeeper and cannot be fought. In the worst possible ending, the entire world is destroyed, killing all remaining monsters including the cat shopkeeper.

You can choose to kill a variety of dogs in the game, but it is not recommended as the good ending" of the game involves sparing every creature you run into

Various animals can be killed.

Froggit attacks include swarms of flies

You are all extremely confused about what dog fighting is. Dog fighting is when humans force dogs to fight for amusement, not being attacked by dogs.

There are monster characters resembling other animals - for example, one is a deer - that can be killed.

You can kill animals like dogs, goats, spiders, frogs, deer, fish, turtles, horses and birds.

A horse-mermaid type monster can by killed by the player ingame, but it is optional and discouraged.

A monster in the game's short Hard Mode has snakes on its body.

There is a spider monster, Muffet, who bakes with spiders. In her battle, spider's aid her. If you spare her or eat one of her treats, she's friendly to you.

There is a very difficult-to-find monster encounter which is very dragon-like (and described by his creator as a "butterdragon"). Like other monster encounters, it is possible but not required or recommended to kill him.

In several points of the game, the player can find cameras that are implied to be recording them. Additionally, after exiting the Ruins, there is a short sequence where a character stalks the player which may be triggering to some.

That’s not what gaslighting is.

There are no graphic depictions of child abuse, but there are heavy implications of child abuse in some routes.

There’s a dog who “smokes dog biscuits,” but this is purely for comedic effect and it’s never listed as addiction.

There is a disabled dog named Doggo. He smokes dog biscuits.

There is one NPC in Grillby's known as "Drunk Bun" who could be seen as an alcoholic.

The creation of the Amalgamates is assumed to be torture, but they and their families seem to be fine with being mixed with several other people.

There's potential implications to both shaving and cutting, but nothing explicit

In the true pacifist route, Undyne's house burns down. The house is shaped like a fish so it comedically shows it; the windows of the house are eyes, so there are flames in it and "tears."

Not of humans, but the spider treats are said to be made "by spiders, for spiders, of spiders"

When on the "no mercy" path, after killing one boss his head becomes detached from his body while his body is reduced to dust. His head becomes dust separately. This is commonly interpreted (and regularly depicted in fan material) as being the result of the player crushing his head under their foot.

Yes there's a coffin, but the person in it was not buried alive.

I suppose if you count decapitation, then yes.

There is one character who wears an eyepatch, and a few monsters are based on eyes. No violence is done to eyes unless you perpetrate it, however.

I... I mean... you can kill a skeleton...

There’s multiple people that fall from a large heights, but none of them die

Is one of the plot points but is not graphically showed

When the playable child character is taken in by a motherly goat creature who intends to keep you as her own. She is disappointed when you leave, but understands that you are not her child. Your character resembles the first human child that this motherly goat creature adopted. So implied kidnapping? Additionally a silly skeleton creature “captures” you after he defeats you in battle. You are put into a room with dog supplies and a fence, but can easily escape through the bars to continue your journey.

The parents of Asriel Dreamer, Toriel and Asgore, can be killed by the protagonist. When they are killed, they have slashes across themselves and turn into dust. However it is your choice if they die or not.

After leaving the Ruins (all routes), a door clicks and Sans' shadow appears behind a tree The elevator to the True Lab (Pacifist route) suddenly falls and a siren plays Neither are exactly scary but they made me jump lmao

In the short Hard Mode, there is a special monster encounter with a clown face and described as a "messed-up clownbug".

Though there is a ghost name Napstablook, he is a comical character and does not attempt to be scary in any way throughout the game

A figure can be seen behind a shower curtain, but pulling it back reveals that nothing was there.

A ghost possesses a training dummy but I'm like 99% sure the dummy wasn't sentient before that?

There are whoopie cushions, however.

Portions of Alphys' lab are reminiscent of a hospital.

Not on-screen, but there are references to injections in the lab notes of one character experimenting on other people.

No, although there’s a lab that could look like one.

Alphys has problems with anxiety

Yes, someone slowly dies by poisoning themselves in the backstory.

A character says she had thoughts of “doing something cowardly” during the true pacifist route but she doesn’t go into more detail than that

You are all extremely confused about what body dysmorphia is. Body dysmorphia is not body horror. Body dysmorphia is not gender dysphoria. Body dysmorphia is when a person (usually anorexic) perceives their body to be different(usually larger) than it actually is.

A monster dog amalgamate approaches you in a narrow hallway. They become placid after several pets.

There is one pretty autistic-coded character who is manipulated and taken advantage of by another character but there is no direct ablism

There is one successful and two attempted suicides in the backstory. Furthermore, two characters can commit suicide during the game, one implied and the other on-screen (though non-graphic). Both of them survive in the pacifist route.

The last fight of a Neutral run and Pacifist run can have strobe effects.

The elevators shake a little bit but I don't think it's enough to count?

The fourth wall is broken a lot the more you play the game, with some characters addressing you the player and not the character you play as

Not in canon, at least.

There are multiple LGBT characters who *can* die but they all survive in a pacifist playthrough.

No, overall no one ever comments on anyone else's weight. However, one of the secret bosses, So Sorry, is known for being a character designed by a fat fetish artist.

Not in the game, but the fandom does have issues with infantilizing an autistic-coded character

it's more of a "rectangle in a dress" joke. also, in one of the endings, he gives his dress to a character that is implied to be transfeminine.

This game is known for being extremely LGBT-positive. There are two gay couples who are treated as normal by the narrative.

Who said yes??

Nothing stronger than a character being offhandedly described as "sexy".

Only in the fandom

At one point, you, playing as a character that is presumably a child, can go on a 'date' with Papyrus, but Papyrus either doesn't understand the implications of what a date is or he does and has no actual romantic/sexual intent. Still, worth noting.

It really only depends on what route you play, if you do a genocide Route then of cause there’s not a happy ending, there’s a fair amount of what one would call neutral endings though

You can find a Santa costume in one character's room and a "thank you" letter addressed to Santa in another. These aren't directly spoiling it, tho

You have the option to kill a plane shaped enemy. Their death animation shows them crashing to the ground. This is more comical than anything and the only fatality is the plane monster.

The main character can use an empty gun as a weapon but it isn't really shown as any different than using other weapons. There's also cartoonish guns in one fight

there is eye gore shown toward the very end of the genocide route. there is another instance of possible blood in the genocide route, but considering the character it happens to, it could just be ketchup.