Shown in the book Collecting Pez (author's photos).
1979 PEZ ad sheet is shown below. Also there is a photo from the offical PEZ site showing the collection.
The author of that collector's guide explains: "These 6 items all came from the same former PEZ employee around 1991-1992. A woman who had worked for PEZ in the 80s (and I think still did at the time) consigned them to be auctioned through a dealer. Since the PEZ hobby was very "young" at that time, the true importance of these were not recognized by most collectors. All of these have been sitting in the same collection for 20 years. They were never again on the market.
"Photo (below) is a scan of the original salesman sheet for the Eerie Spectres. It is quite clear that the heads shown are NOT the actual dispensers heads but are plaster mockups or prototypes. Even then, the heads had been chipped and had some paint scuffs as the photos clearly indicate. In fact, taking the Spook and Air Spirit as examples, you can see that the ear tips of the Spook and the point on the top of the head of the Air Spirit have been color retouched on the ad sheet to cover defects on those tips.
"Since obviously another 10+ years intervened after the ad sheet photos were taken, when they arrived to me, they had even more chipping and paint loss than in the photos. But in the comparison of the heads in current state to the photos, you do see many of the same defects.......in some cases the defects got worse........but it helps to satisfy us that these are likely the VERY SAME prototypes shown on the ad sheet."
These are for sale as of this posting date (see EBAY).