A great name—possibly inspired by “The Thing in the Crypt,” the Conan story by L. Sprague de Camp and Lin Carter?—for a tomb guardian with some tricks up its sleeve. Unlike most undead, crypt things are quick, with Alertness, Dodge, Improved Initiative, and Lightning Reflexes to show for it. And thanks to its quickened dimension door and teleporting burst abilities, the crypt thing is a master of space within its small, circumscribed world.
The Maul of Storms sits atop a cairn in the center of a great glacial cavern, accessible only by a simple stone bridge. The crypt thing who guards the magic maul has a nasty habit of teleporting offenders onto the sheet of ice that surrounds the cairn—ice that shatters like glass in all but the coldest months, pitching the thing’s victims into the frigid black waters below.
Ephraim the Deathless is the default ruler of a small necropolis in the City Below. The other intelligent undead who have flocked to his domain name him a lich, an assumption he has not discouraged. In truth, Ephraim is a simple crypt thing, following his master’s dying instruction to watch over the necropolis and preserve the amulet he now wears around his neck.
Not all crypt things are found in crypts. The Special Collections room in the library of Alinzeria is gated off and may only be entered by senior scholars. Interlopers are met by a crypt thing, a former head librarian, who can not only teleport foes, but also burn them with a cold fire that boils blood but leaves the stacks’ librams untouched.
—Pathfinder Bestiary 2 60