The deceased king was assimilated to Sokar in his henu barque1, which helped travelling in the underworld. This barque on a stand has the head of an antilope at its stern and contains a sacred relic within a mound
with sometimes an emerging image of Sokar as a seated falcon serekh like. Such compositions in glass or sheet gold of the Late Period are very rare2

Broken blue glass with emerging serekh W 3.4, H 3.4 Late Period-Ptolemaic Period MET #17.194.2495

Sheet gold W 1.6, H 1.6
Ptolemaic Period
Art market
Unscaled picture

Red glass L 3.6, H 2.2, T 0.4
Ptolemaic Period
© 2013 Musée du Louvre/ Antiquités égyptiennes
#E 2252

References

1Wilkinson R H. The complete gods and goddesses of ancient Egypt, 2003, Thames & Hudson, pp. 209-211
2Unpublished amulet