https://www.gamespot.com/articles/whats-up-with-fortnites-cube-season-6-theories-upd/1100-6461878/

Fortnite's otherworldly cube continues to trudge along on its journey of destruction. But what does it all mean? The fans have passionately followed the exploits of the cube, and while its eventual Season 6 implications are still shrouded in mystery, the community is pretty sure it's nailed down where it's going. [Update: The cube has indeed made its way to Loot Lake, where it sank or melted. The water is now purple and causes you to bounce, just like the cube did.]

A thread on the Fortnite subreddit has been tracking the cube's movements, and even predicting them with some success. The cube, affectionately nicknamed "Kevin" and sometimes referred to as a "he," has been sporadically changing its movement intervals and direction. Fans quickly realized that the runes it was "printing" in select spots on the map drew an image of a 3D cube. Kevin is very body-positive about his shape, apparently.