I have a couple antique stereoscopes but I don't have anything nearly as brilliant or unique as this set of slides entitled "The Goblins will get you if you don't watch out". Ah, early 20th century parenting. I also don't have the means with which to afford this set which recently appeared on eBay via PK General Store.
With modern eyes, a number of the goblins seem pretty whimsical, practically gormless but the one featured in the image above is pretty sinister with its empty eye sockets and Donnie Darko-like ears. I've always had a deep interest in the era and these are a revelation.
PK General Store (eBay) - SOURCE
The Hysterical Society (Tumblr) - SOURCE
Stereoscopes (Collector's Weekly)