Wondrous item, very rare
This helmet is made from the skull of a walrus, and is covered in symbolic patterns of ritual significance.
While wearing the helm, you can use an action to unleash a sonic cry in a 30-foot cone that is audible 600 feet away. Each creature in the cone must make a DC 15 Constitution saving throw. On a failed save, a creature takes 5d6 thunder damage and is deafened for 1 minute. On a successful save, a creature takes half as much damage and isn’t deafened. Creatures and objects made of glass or crystal have disadvantage on the saving throw and take 10d6 thunder damage instead of 5d6.
Additionally, as an action, you can unleash a high-pitched cry, similar to those that whales and similar creatures use to communicate. This cry can be heard up to 1 mile away with a DC 5 Wisdom (Perception) check.
Finally, you can speak with aquatic mammals (such as dolphins, seals, and whales) as though using speak with animals.
Each time a whalebone helm’s sonic cry or highpitched cry is used, there is a 10% chance that it shatters into a thousand pieces, dealing 8d10 points of piercing damage to you and rendering it permanently destroyed, unable to be fixed even by magic.
Pirate Campaign Compendium © 2018, Legendary Games; Lead Designer Jason Nelson. Authors: Alex Augunas, Jeff Gomez, Matt Goodall, Jim Groves, Tim Hitchcock, Victoria Jaczko, Jonathan H. Keith, Lyz Liddell, Thomas J. Phillips, Alistair J. Rigg, Alex Riggs, Loren Sieg, Neil Spicer, Todd Stewart, Rachel Ventura, Michael D. Welham, Linda Zayas-Palmer.