For many years I mistakenly believed this was produced by Beistle due to the imagery. It was only when I couldn't find any reference to Beistle actually producing such products that I looked closely at the artwork and noticed many differences between the art in such things as their Party Books and hats and this horn. It finally dawned on me that this horn was almost surely an authorized adaptation of Beistle imagery. There is a likelihood the horn was made in Japan, but I don't know this for certain. In any event, it is a nice item, and still has a SGV of $125, but it wasn't made by Beistle.
Mark B. Ledenbach's vintage Halloween collectibles blog.