There are two types of these green-faced beings, in sets 9411 (both) and 9408 (tall one only).
They are hard to pull apart becasue of their neckwear and helmet, but I managed it, here are the results.
1. Alien, Sykronian Leader (aka Boss Sykronian, short Sykronian)
Has a normal head (interchangeable with most other klickies), torso, skeleton and arms (with
Dynasty shoulder extensions) and dwarf legs.
2. Alien, Sykronian (aka Expendable* Sykronian, tall Sykronian)
Has a head which is interchangeable with some other Super4 figures (Alex, Ruby, Gene) and (I think) the
Spirit figures with slim torsos. Torso, skeleton and arms are different from those of typical klickies.
The two heads together:
* When we watched the original TV series of Star Trek, my brothers and I always referred to extras in James T Kirk's landing parties as Expendables. They ALWAYS ended up getting fried (or disolved, or eaten, or whatever). And, rather neatly, these Sykronians' faces resemble that weird alien face which appeared behind the Star Trek end credits. Happy DAys!