The Halloween Watchers

Behavior
On Halloween night, costumed beings always wearing masks will occasionally come out of nowhere and watch people from a distance. Any attempt to approach or attack them will prove fruitless because they always somehow escape before anything can get to them.

Trivia

 * From the image, we can see costumed beings dressed as an animal and Sans. The animal costume can be assumed to be worn by a furry. The Sans costume is an obvious reference to Sans from Undertale.