I found this horrifying stamp affixed to a parcel sent from the United Kingdom -- at first I thought the leering death-mask of Chthulu had been chosen by the Royal Mail as a subject for a series of collectable demon postage.
Upon studying the writing more closely, I discovered it was actually the Aztec god Xiuhtecuhtli.
Feasts were held in honor of Xiuhtecuhtli to keep his favors, and human sacrifices were burned after removing their heart.
Right, that'll be 47 pence. Cheerio!