The prop skull used in the famous Gravedigger Scene in Shakespeare's Hamlet.
Excerpt of Act 5, Scene 1:
First Clown
A pestilence on him for a mad rogue! a' poured a
flagon of Rhenish on my head once. This same skull,
sir, was Yorick's skull, the king's jester.
HAMLET
This?
First Clown
E'en that.
HAMLET
Let me see.
[Takes the skull]
Alas, poor Yorick! I knew him, Horatio: a fellow
of infinite jest, of most excellent fancy: he hath
borne me on his back a thousand times; and now, how
abhorred in my imagination it is! my gorge rims at
it. Here hung those lips that I have kissed I know
not how oft. Where be your gibes now? your
gambols? your songs? your flashes of merriment,
that were wont to set the table on a roar? Not one
now, to mock your own grinning? quite chap-fallen?
Now get you to my lady's chamber, and tell her, let
her paint an inch thick, to this favour she must
come; make her laugh at that. Prithee, Horatio, tell
me one thing.