The lovelorn sand-ooze boss (Mrs. Ghazi), a level-52 borough boss defeated when Carl burns its core — collapsing the whole castle.
The Sand Ooze — formally 'Mrs. Ghazi,' a level-52 borough boss and minion of Psamathe — gets a mournful, joke-free system entry musing on a loveless creature bound to guard a man who doesn't love it back, unable even to end itself because its master revives it. Hunting by vibration, it's kept busy by Katia Grim's thrown debris and a bass-heavy trap sphere while Carl ceiling-walks to its exposed yolk-core beneath the recliner and torches it with Burn Gel. It surges, flinging the flaming chair, and folds in on itself trying to smother the unquenchable fire; its health bar drops and it dies, opening the quadrant.
Its death (and the heat) collapse the crystal chamber, and the ensuing flood washes its remains — and Carl and Donut — into the water quadrant. Because Psamathe still lives, in principle a single grain could regrow it, but with the castle gone and the quadrant liberated, it is functionally destroyed.
A vast sheet of grey sand moving like slow gray lava, mixed with hitched-along magazines and lab junk; a yellow yolk-like core dome glowing beneath the recliner.
The land-quadrant boss — a tragic, near-immortal ooze slain by fire to open the quadrant.