There appears to be a number of times that bones or an excess of bones appears in the Magnus Archives, included here are extremely sharp bodies that may be caused by bone.
Appearances of Bones
Bone book (MAG 4)
Pipes of Bone (MAG 7)
The pipes that the piper plays is made of scrimshaw bone.
The Boneturner's Tale (MAG 17)
Jared Hopworth found a book entitled The Boneturner's Tale, he seems to have been able to learn how to absorb or remove bones from people and animals without killing them. He appeared to have added more bones to himself.
Michael (MAG 26)
Michael seems to be some sort of entity or creature that looks like a man, except when viewed through distorted glass or reflections. When seen this way, he seems to have long limbs and giant hands.
The Student's Bones (MAG 34)
The seven students who learnt anatomy from Lionel Elliot were able to change their bone's shape with an unsettling crunching noise.
Grifter's Bone (MAG 42)
The esoteric musical group whose audience kills itself is named Grifter's Bone.
The meaning of bones
"You’re thinking too literally. Examining the physical categorization, but ignoring the meaning of the thing. What are the bones? In the Distortion, your “Michael”, the structure of a skeleton, an established reality in your mind, is twisted and warped into an impossible form. But in other cases? Are they a symbol of slaughter and butchery? Are they the familiar made wrong? Or are they simply part of the messy, physicality of flesh?"