Zashoth, Horror of the Deep

{8}{u}{u}: Monstrosity 5 (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous)
When Zashoth, Horror of the Deep becomes monstrous, destroy all other non-island permanents.
There are ancient stories of a horror that hides in the deep seas and can destroy giant fishing ships with its teeth larger than their masts.