How to setup a custom penetrator:
1. Mesh Setup
1.1 If your penetrator is rigged and should support dynamic bones it has to meet the following requirments:
Local Position and rotation of the Armatur, Mesh and Bone object has to be zero.
Scale of these objects should be 1
1.2 The mesh, armature and root bone need to have their forward vector pointing towards the penetration direction
1.3 The root position of the mesh should be where your penetrator should start being influenced

Exporting a Penetrator correctly from blender is a fucking pain, cause blender fbx to unity export SUCKS ASS!
I appended two pictures of armeture rotation in blender + export settings that worked for me.