I'll bump this thread up with more creepy things.
This time here, I'll focus more on spin-offs and console ports. Everything is from either my experience or from what I've read.
- Mutant plant: Before the known and loved Cow plant, there was mutant plant from The Sims Bustin' Out for home consoles. Sims who use the incubators can create it. If your sim takes good care of it, they can sell the plant eventually. If not, the plant grows bigger and starts eating sims (though not all attempts are successful). While cowplant just sticks its tongue out with a cake, luring sims into it, the mutant plant literally jumps to catch those sims. Imagine being chased by a mutant plant trying to eat you. Terrifying!
More about mutant plants: https://sims.fandom.com/wiki/Mutant_plant#The_Sims_Bustin.27_Out
- Veloci-Rooster: Imagine just walking around a town when a fast mutated rooster suddenly comes and knocks you out. That is what can happen in The Sims Bustin' Out for GBA. Your sim will pass out, wake up in hospital, and when they come home, they'll have doctor's bills. And if you don't pay bills there, your sim goes to jail.
More about that here: https://sims.fandom.com/wiki/Veloci-Rooster
- Earthquakes: In The Sims 2 Castaway for home consoles (Wii, PS2), there is a chance for earthquake happening, destroying the structures your sims have built (yes, sims have to find resources and build it by themselves). When this happens, a cutscene will play. And they reused The Sims 1's danger theme in there (you know, that soundtrack that plays when a burglar comes).
- The possibilities in The Sims Medieval: In The Sims Medieval, there are things that won't appear in the mainline games. Sims can get drunk by alcohol. Sims can literally murder each other by swords and poison. And sims can be punished with death. Don't worry, it's sim being pushed into a pit occupied by Pit Beast, with whom that sim has to fight to. Some survive, while others get eaten while trying to climb out, with the beast later spitting the bones of the sim out. There are a lot of skeletons in The Sims Medieval...
- Removed mourning: Let's go to freemium games! Yay! In The Sims Freeplay, when aging was featured adding death by old age (sims can die by only old age there), sims mourned when a friend or family member died. They could do two interactions with other sims to get over it faster, but until then, they moped around and were sad. Then at some point, it was removed. If a friend or family dies now, sims won't care. If they are happy, they'll be happy, walk happily, and so on (or shall I say inspired). It's like they never existed. But hey, you now have that senior's life orb which you can use to build a arcade, a beach, a carnival, and a pet park! Yes, sims need to die for it or you can use the premium currency.
- Grim Reaper stalks old sims: Well, it was a thing in The Sims Freeplay and The Sims Mobile, but it's also removed. When senior/elder sim was close to death by old age, Grim Reaper used to stalk them, and in The Sims Freeplay, use objects like TV, grill, and so on. Sometimes he would try to eat an apple and fail, then try to throw the apple into his hood, only to fall out under him. At other times a dove flew on his arm and immediately died and fell on the ground, making Grim sad. It lasted until the senior/elder died or got their life extended.
- Grim Cowboy: In most of the handheld games (and in The Urbz: Sims in the City and The Sims 2 Pets for home consoles), sims didn't die. Instead when they were starving too much, they passed out and waked up at their home, hospital etc. Sometimes there are a character who collects the passed out sim, for example a genie. In The Sims 2 for DS, it's a brown ghostly figure wearing a large hat. In game, it's called Grim Cowboy. So yes, don't let your sim pass out there by hunger, thirst, poor hygiene, freezing in freezer, burning in fire etc.
More about that here: https://sims.fandom.com/wiki/Grim_Reaper?file=Grim_Cowboy.jpg#The_Sims_2_.28Nintendo_DS.29
