The Alien Combine Soldier is an enemy cut from Half-Life 2 and the predecessor of the Overwatch Soldier. Like most of the Synth or alien-style soldiers, the concept was abandoned to avoid any direct representation of human-scale alien enemies and instead depict the Combine as a more elusive force. Its design was probably recycled for the Combine Advisor and somehow inspired by the Kingpin, an enemy cut from Half-Life.
It was to move like a snake or a worm. Another version was to have dingy yellow polished skin, yellow lenses, use an energy whip at close range, and wear thick plastic gear with an insignia in the back.