So today, I was battling some monsters on the roof of my house with a friend who I shall refer to as "TG". After it had turned into daylight, I decided to jump into the ocean to make a battle arena... but I noticed something strange... there was a perfect cube of sand going all the way down to the ocean floor, and diagonal turrets of sand that made it look like a lopsided "D" shape... I called TG over, and I explored a bit... that's when he summoned me.
He was exploring elsewhere underwater, and came across a cave that was covered with half steps that floated on their own... it had a small waterfall and an air pocket, but it didn't lead anywhere. I tried to ask the server host who made it, but they had suddenly logged off without even saying anything.