A hypocephalus is an Egyptian amulet that is normally found underneath the head of an Egyptian mummy (Egyptian Mummies, by Carol Andrews, The Trustees of the British Museum, 1984). Most hypocephali are "maufactured of stuccoed linen, and more rarely of papyrus or bronze." (Mummies and Magic, Museum of Fine Arts, Boston, 1988). On the hypocephalus is inscribed with the Book of the Dead Spell 162, a "spell for providing heat under the head" (ibid.)
Typical drawings on a hypocephalus include, the cow-goddess Hathor, four sons of Horus, the God of Min (part bird and part man), the sun-god, Amen-Re, Isis, Nephthys, moon-boat, seated baboon representing Thoth, boats of Sokar-Re, and a scarab.
So what does a "hypocephalus" have to do with Mormonism?
You may be surprised that you can find a hypocephalus in the LDS Book of Abraham. It's very easy to identify. Take a look at facsimile no. 2, which is supposed to be "FROM THE BOOK OF ABRAHAM".
I have reproduced a number of different examples of hypocephali at my web site. You can see them by visiting my page at:
Joseph Smith clearly associated this Egyptian amulet with the Book of Abraham. He even interpreted many of the common hypocephali figures.
I encourage you to research this issue in more detail.