Great Golem of Prague
The golem designed and implemented by the wizard-rabbi Judah Loew ben Bezalel in the late 1500's.
The Jewish ghetto of Prague, mostly defined by the area now known as Josefov, had begun once again to suffer anti-Semitic attacks during this period. To protect the Jews of the Ghetto, Judah Loew decided to build a great Golem to patrol the streets by day and night, stopping intimidation and violence wherever it found them.
For this purpose Rabbi Judah took a great mass of clay from the banks of the river Vltava, and spent three days and three nights reciting over it both a complex spell in the Speech and verses from the Sefer Yetzirah over the construct (1). To further reassure those of his co-religionists who were not quite sure what wizardry's source was, Judah inscribed on the near-finished golem's chest the Hebrew letter emet, standing for "earth", (thus inviting comparison with the way God had been said to have created Adam). On the morning of the fourth day the creature rose up, fully animated, and set out to patrol the Ghetto.
Unfortunately Rabbi Judah had miscalculated the power of his spell and (according to later analysis by experts) had transposed or misstated several key variables, particularly the one invoking the concept of continuous creation. (2) As a result the golem secretly returned to the banks of the river between midnight and four AM each day, and continued to augment its substance. It grew far beyond the size which Judah had planned for it, and the resultant derangement of the power equations in the spell -- which kept increasing themselves to keep up with the golem's physical growth -- caused the spell's control functions to catastrophically fail. The golem became both huge and violent, terrorizing not only those persecutors it had been designed to defend against, but the people of the Ghetto, whom it had been meant to defend.
When he realized what was happening, the horrified Judah immediately prepared to deactivate the golem. Along the way to achieving this goal, he had to first make it impossible for the golem to acquire any more mud from the Vltava river. This he did by placing a truly massive stasis spell on the water of the river, keeping it fixed in one place, and then extracting all water from the clay of the banks, leaving all of it as dry as dust for a mile up the river in either direction. He then had to physically overcome the golem, maintaining contact with it long enough to revoke the wizardry (and incidentally effacing the first letter of the word emet in the process, so that what was left was the Hebrew word met, standing for death or destruction). The Great Golem then disintegrated, shattering into many huge pieces.
After this tremendous conflict, Rabbi Judah was rather frantically reassured by the Prague civic authorities that there would be no more attacks on Jews. However, though still profoundly upset and embarrassed over his huge error he was not above keeping the Great Golem's remains around as a reminder of what kind of power could be exerted on his people's behalf if necessary. The shattered clay pieces were gathered together and put into a coffin which remains to this day (it is said) in the genizah or "retired holy document repository" in the Altneushul (Old-New Synagogue) in Prague. The legend which was allowed to grow up around the remains says that the Golem can be made to rise again when the people of Prague are in need. Possibly as a result of this, in local Czech culture, the Great Golem is now quite popular, appearing in the names of businesses and restaurants.
(See also: Construct, Inhabition, Inanimate object, Lifewords.)
(1)This book of ancient Jewish mysticism, also known as the Hilkot Yetzirah ("Rules of Creation") is incorporated as a limited-access section of the Wizard's Manual.
(2)It is possible that this was due to one of the "purposeful" typographical errors in the Sefer Yetzirah. A similar on-purpose error is described in the front matter of SYWTBAW, in the quotation from the Mishnah.