On the “Zero Hour” mission attack the Zerg base that is located to the north/north-west of the map. You will find the neutral Marauder.
If you simply left click on him a few times then eventually the text “Secret 3…2…1″ will appear, and then the Marauder will disappear!
unless the tauren is at the north east base. meh i could be wrong
Its not a neutral maurader i beleive. you can get just close enough to him with a single marine hes actually a Lvl 80 Tauren Space Marine