The Glass Desert

The Glass Desert is an area that was added in update 0.6.0. It's very far from the mainland of the Far Far Range, and is only accessible through a teleporter located in The Ancient Ruins. It's a barren wasteland covered with giant glass structures that create ultra hot anomalies. This harsh environment has little hints of what it once was, and you might be able to bring it back. It acts as the end-game zone, and has many challenges not found in other zones. Four new slimes called Mosaic Slimes, Tangle Slimes, Dervish Slimes, and Fire Slimes live in this place.

Slimepedia Entry
The Glass Desert is mostly uncharted territory within the Far, Far Range, located so far beyond the ranch it is only accessible via teleportation.

The Glass Desert gets its name from the monolithic glass structures that dot its landscape. Resembling prismatic, frozen flames, these glass structures are believed to have been created during a violent solar event, scorching the land and stone into glass. These glass structures are also believed to be the catalyst for the dangerous solar anomalies that regularly occur in the Glass Desert: firestorms that burst from the ground, as if intense heat is desperate to escape the ground below.

But the desert's barren, unforgiving, sometimes violent environment hides a secret: somewhere deep within it lies a memory of what once was, and a means of restoring parts of that memory.

Trivia

 * There is an achievement named Smoke, Fire, and Mirrors, which is unlocked when visiting the The Glass Desert. This achievement was implemented before The Glass Desert was added, making it impossible to achieve.
 * The Meteor Slime, which was once intended to be in this place, was scrapped because the slime wasn't "working" but it is replaced by two upcoming slimes. However, it is known if it will come back in the future.
 * A puzzle similar to The Ancient Ruins can be found at the entrance, requiring five Quantum Plorts.