I disagree with using Zerg for the very simple reason being that it's not what they say. Zerg is zaagu [ザーグ], not zooku [ゾーク], which is pretty distinctly different in Japanese. In any case, I vote for keeping it as Zork/Zorc.
For all we know, it's an in-universe term, and isn't meant to have a real-world counterpart, but just make it sound cooler or easier to remember than "dream break". If we're grasping at straws for a reference, it could be one to the demon lord Zorc from the Yu-Gi-Oh! tactical RPG