Rare Shield, Requires Attunement

Minotaur War Bell. When you are missed by an attack, you can spend your reaction to ring the bell on this strange shield, forcing every creature within 10 feet of you to make a DC 13 Constitution saving throw, taking 1d10 Thunder damage and becoming deafened until the end of their next turn on a failure. 

Gangplank. As an action, you can put “Walken” on any surface and extend it into a 30-foot long and 10 foot wide wooden bridge, with one of its ends being within 5 feet of you, and the other in a place of your choosing within 30 feet of you.
The bridge will stand on any liquid surface as if it were harmless solid ground and cannot be submerged or destroyed.
At least half of the bridge must be standing on some kind of surface, otherwise it will immediately crumble and turn into a shield again.
You can then use a bonus action to return “Walken” to its shield form if you are touching it, when you do so, the bridge disappears and any creature standing on it will suffer the consequences thereof.

Water “Walken”. The shield gives you the ability to walk instead of swim while completely submerged underwater. You can use your normal speed instead of swimming speed while submerged in any liquid.
You also gain the ability to breathe underwater.