3D model taken from http://roestudios.co.uk/project/3d-pokemon-models and edited with Meshmixer/Blender for desired result. Feel free to remix.
Pokemon Copyright Gamefreak/Nintendo
I will eventually make a Gastly that has the fumes around it and add it to this, but that is currently beyond my skill.
Fused the arms for Haunter to its body... it looks dumb.