Simple Geometry Shader


I have been googling how to implement simple geometry shaders into Unreal Engine 4.
To give you an example, I have uploaded a picture + HLSL code ( SpikeyBoiShader.txt (2.59 KB) ) of a Spikey Shader. I want to be able to achieve this in unreal engine 4.

Is this possible? Or is it impossible?
Do I do it with Materials and the Custom Node?
Or do I follow this:

Im quite confused as to how to begin…

Thank you for your time.