JudgeMental said:

This artifact, known as the “Devil in the Glass” (Teufel im Glas),
is a 17th-century curiosity currently held in the collection of the
Kunsthistorisches Museum in Vienna.

The object is a small, solid glass prism (approx. 6.6 cm tall)
containing a tiny black figure.

It was originally part of the collection of Archduke Leopold Wilhelm
in the mid-1600s.

By 1720, an inventory in the Imperial Treasury (Kaiserliche Schatzkammer)
described it as a spiritus familiaris—a familiar spirit or demon—that had
supposedly been exorcised from a possessed person in Germany and
banished into the glass.

In the 18th century, the Treasury presented it as physical evidence of
successful exorcism and the reality of supernatural forces.

Modern analysis identifies the “demon” as a small figure made of black
lead or a similar dark material that was cast or placed inside the glass
during its manufacture.

While it belongs to the Kunsthistorisches Museum, it is often displayed
at Ambras Castle in Innsbruck, which houses the Archduke’s “Chamber of Art
and Curiosities”.

This artifact serves as a notable example of a Wunderkammer (cabinet of curiosities)
object, where natural or man-made items were often given mystical backstories to
enhance their value and wonder.

I like that object. Ta.