[Endoperez]

If the golem had enough gems, it indeed sounds like a bug.

Vis means gems. The term comes from Ars Magica, a roleplaying game. It is used for magical resources that can be used to create magical items or to help the mage to complete a more powerful spell. Most vis is aligned, e.g. Ignem (fire) vis might come in the form of rubies, or Auram (air) vis as wingbones or feathers of a magical bird.