The Lost Pyramid of Khamandides was raised up in the Sahara Desert, at some past time long lost to history. Unlike other known ancient pyramids, however, no ancillary structures of any sort were near it; and it stood as a solitary entity.
The Salar explorers Wilson and Lindsey rediscovered the pyramid, after much theretofore-futile effort. They found its outermost surface covered with hieroglyphic inscriptions, which Lindsey could translate: "This is the great tomb of the King Khamandides, The God of the eternal fountain..."
At that moment a door mysteriously swung open in the side of the pyramid, and they entered - but it then closed behind them, trapping the pair inside. Their explorations led Wilson and Lindsey deeper within the pyramid - and there, indeed, was an eternal fountain, surrounded by treasure. By then, though, heat and dehydration had taken their toll on Lindsey, and he went mad...
Nor was this the pyramid's only secret: it was inhabited, by a mysterious race called the Zombites, who'd made it their hidden base - and who clearly thought everybody were uninvited...including Scott Tracy, who'd tracked down Wilson and Lindsey in an attempt to rescue them...
The Lost Pyramid appeared in the episode The Uninvited.
At least two cutaway drawings exist of the pyramid. Both were illustrated by Graham Bleathman.
The first appeared in a Fleetway comic in the 1990s, and the other featured in a Redan comic.