From Creatures Wikia
Version 2.1 is renumbered from 211 to 212 to avoid conflict with Grendel Guard.
This COB, made by Slink injects a rain cloud which travels across the Albian mainland from the grendel tree to the watchtower. It originates in the thunderheads near between the grendel tree and the island. It begins to rain when it hits the mainland, and ceases to rain soon after it crosses the mountains near the watchtower. It evaporates completely before reaching the desert island.
Rain is pleasant for your norns, but there is a 1% chance that lightning will strike. This is more fun for your norns to watch than for them to feel. It will not inflict much damage if it strikes them.