The Witcher Bestiary - Golem
Golem Occurrence: A golem is a creature made of stone or wood, brought to life by a mage and animated with the use of magic.

Immunity: Its tough body is immune to sword blows and most effects.

Susceptibility: A golem can be stopped by its maker; usually the giant is set in motion by a lightning bolt, so a major electric shock might incapacitate or even annihilate it.

Tactics: A golem uses its superhuman strength to knock down, stun and crush opponents.

Alchemy: Golem's obsidian heart.

Once an absent-minded mage created a golem, animated it by casting Alzur's Thunder, and ordered his new servant to fetch water, before burying himself in his scholarly books. The golem kept carrying water day and night, without pause, and ultimately flooded not only the mage's house, but the whole city. As you can see, my young students of the Art, improper use of tools and a lack of elementary training may cause a tragedy.

- Anabelle Radfind, Lectures on Security and Hygiene in Magic