The Alien is unique among Zeroids. First, it explodes! Not literally of course, but in the manner of all wonderful 60s and 70s exploding toys – it falls apart. The head and several of the parts pop off when it reaches the end of a path that is programed into it.
Second, you can prorgram it! Sort of. When assembling it from the parts that will eventually blow off, you place a gear inside that determines the Zeroid’s course.
And lastly, the thing is a cyborg alien. All the other Zeroids are just straight up robots.
A very cool toy, and one of the nearest Zeroids I’ve seen.