Way off in space somewhere a war criminal is sentenced to be death, but, before he can be executed, he escapes and makes his way to Earth where he's run over by some people driving around in the woods in a RV. They take the injured man to a park ranger and suddenly a freaky-looking creature with a laser starts shooting at them.
Other stuff happens, but none of it matters. The entire film is shit. The script seems like it was written on the spot, the forest scenes are boring, the space station scenes look like they were filmed at a power plant, the acting can barely even be defined as acting, the special effects look really cheap, P.J. Soles slumming.
From the opening scene to the closing shot ALIENATOR is a massive bore. Not even worth laughing at. Skip it and never look back.
That's as wide as the door opens.