Some fanart for the Locked Tomb, featuring a bone construct depicted in the book. The description is copied below.

"When her eyes cleared, Gideon was confronted with the biggest skeletal construct she had ever seen. The room was full of it, bluely aflame with Isaac’s light, a massed hallucination of bones. It was bigger by far than the one in Response, bigger than anything recorded in a Ninth history textbook. It had assembled itself into the room by no visible means, since it never could have fit through one of the doors. It was just simply, suddenly there, like a nightmare—a squatting, vertiginous hulk; a nonsense of bones feathering into long, spidery legs, leaning back on them fearfully and daintily; trailing jellyfish stingers made up of millions and millions of teeth all set into each other like a jigsaw. It shivered its stingers, then stiffened all of them at once with a sound like a cracking whip. There was so much of it.

Everywhere she looked was filled with construct: everywhere Isaac’s light touched there was a veritable cancer of bone and tooth.

Isaac’s blue-green fire fell upon a giant trunk of bone, a skull terrifically mangled into the thing’s only coherent core: a simulacrum of a face with closed eyes and closed lips, as though locked perpetually in prayer. This vast mask loomed down from the ceiling and strained beneath Isaac’s pull."