Eli Eshed has a really nice post about Chelm and the 16th century Rabbi Elijah, the Ba'al Shem of Chelm's golem (link). I have previously posted en passent about Rabbi Elijah, as famously referred to by Chacham Tzvi and R. Jacob Emden (link), and how they were descendents of his, not grandsons.
Eli refers to a famous account of it in a letter printed in 1674 - less than a century after R. Elijah lived. I believe Gershom Scholem first called attention to this letter. I figured I would post it.
It appears in a mammoth work called Sota by Johann Christoph Wagenseil. It is in the section of notes sent to him by Christopher Arnold. Here is the relevant excerpt:
It describes how the golem is created from lime for being a servant, to do housework. It is animated by writing 'Emet' (truth) on its forehead. But it keeps on growing and gets stronger. To cause it to stop, the thing to do is to erase the aleph, leaving the word 'met' (dead).
He says that the Jews in Poland say that one Elias Baal Schem, the name being derived from those who practice magic using divine names, created such a golem. The problem is that the golem grew so big that he couldn't reach up and erase the aleph. So he ordered the golem to bend down and take off his boots. Upon removing the letter, the heavy golem fell onto him and crushed him.