phys_bone_follower

This entity is not in the stock FGD files by default. It should not be placed (in Hammer) because it won't do anything.

Code classes:

• CBoneFollower
• CBaseEntity (all ents)

phys_bone_follower is a point entity present in all Source games. Apparently, this entity represents the solidity of an individual piece of a CDynamicProp's physics mesh.

Tip: These entities will count toward the entity limit! This can be avoided by deleting the .PHY file from the MDL, or by setting Disable Bone Followers (DisableBoneFollowers) to Yes. Both of these will cause the model to not collide and move as it should.