Answer:

skull

Answer	Crossword Clue
SKULL	Item on a pirate's flag
SKULL	Pate base
SKULL	Cranium

SKULL	Brain protector
SKULL	Image in Dali's eye-tricking "In Voluptas Mors"
SKULL	Crossbones' partner
SKULL	Hard head?
SKULL	King Kong's island
SKULL	"Hamlet" prop
SKULL	Skeleton topper
SKULL	Anthropologist's find

SKULL	Halloween decoration
SKULL	Crossbones' accompanier
SKULL	Red ... ("Captain America: The First Avenger" villain)
SKULL	.. and crossbones
SKULL	Jolly Roger depiction
SKULL	Pirate flag depiction
SKULL	.. and crossbones (pirate flag)
SKULL	Haunted house dangler

SKULL	Jolly Roger symbol
SKULL	Head case?
SKULL	Partner of crossbones
SKULL	Poor Yorick, in part.
SKULL	Prop for "Hamlet," Act V, Scene 1.
SKULL	A handful for Hamlet.
SKULL	The last of Yorick.
SKULL	... practice (blackboard briefing).

SKULL	Yorick in the churchyard.
SKULL	Head.
SKULL	Bones' partner.
SKULL	Jolly Roger emblem.
SKULL	Pirate-flag emblem.
SKULL	Image on a Jolly Roger
SKULL	Kind of practice
SKULL	Kind of cap or session

SKULL	... and crossbones
SKULL	Part of a Jolly Roger
SKULL	Jolly Roger feature
SKULL	Frontal-bone locale
SKULL	Head of the anatomy class