Said to be an entire sapient kelp forest dwelling somewhere on the ocean floor. Zomachubh is passive, and seems content to ignore the sealife that lives inside of it or feeds on it. However, should there be a threat against its existence, the kelp hive mind will attack whatever threatens it, using each strand of seaweed the way a tentacled creature might use its tentacles.
In at least one myth, it was capable of speech. It spoke with what seemed to be thousands of voices at once.