Eve is a disturbing character given her casually-shared death threats, like telling Kate to go for Garth's throat if he gets out of line in a sweet, motherly tone. Not to mention how she spends most of the first movie looking this close to snapping. And she does nearly murder Humphrey on the spot when she thinks he and Kate actually repopulated. When she's told that he actually helped Kate instead, Eve stops strangling the poor guy and comments about how he's "such a nice boy" as if nothing happened. She's also this in-verse, as even Winston and Tony know better than to cross her.
En route to Jasper Park, Kate has a nightmare of the wolf packs fighting. This includes a scene of her father being attacked as she watches helplessly, unable to stop it or save anyone.
Although it's filled with awkward moments, the scene where the bears corner Kate and Humphrey atop a log jutting out of a mountainside is still pretty creepy. Especially when you see just how high up they are (as they are on a mountain) and that the bears mean business. There's also when you just know that the bear cub's mother is gonna show up after he starts crying. That the bear makes her presence known to Humphrey via *Drool* Hello just adds to it.
The confrontation between Winston, Tony, and the two packs is a bit disturbing in itself with all the growling and the rising tension. The wolves look far more menacing than before, and their teeth are much more prominent. It also signifies the moment when Tony intends to live up to his threat of war, and shows that Winston won't back down. Although, the creepiness of the scene is undercut by the Big-Lipped Alligator Moment mentioned on the main tropes page.
It's a brief moment in The Legend of Saw Tooth Cave, but seeing Kate get into a feral, snarling way, complete with a Nightmare Face, when Frieda and Fran refuse to tell her where Runt is manages to be pretty creepy. She likely got it from her mother.
If you thought King was bad, the Head Wolf of Daria's pack is worse. He outright tries to murder Daria in cold blood because of her blindness, and then later tries to again after she's grown up. Not to mention how he murdered Daria's mother for defending her, which makes his Karmic Death mentioned below all the more satisfying.
The ghost itself manages to get a few moments, mostly because of how it manifests as a Mysterious Protector. Not to mention when after it's implied to be Daria's mother, it utterly snaps and kills the Head Wolf in a flash of light.
During the climax of Family Vacation, Humphrey backtracks and goes after the trackers to keep them from catching up to his family. He actually lunges right at the camera when he reaches said trackers, going into a rather feral mode. It's not unlike the Kate example from Legend of the Saw Tooth Cave mentioned above.