My original tumblr post was here. This image was first posted on tumblr by http://kgthunder.tumblr.com/post/21292255739″>Badaxe and comes to us via dashtxt. It appears to be a crop from a cover illustration for a German sci-fi magazine called Perry, where it appears to illustrate a story called “Der Super-Mutant.”
Found, in a gallery of similar covers, here.
that is a spinoff form “Perry Rhodan” – the worlds best selling SF series EVER (more then 2800 issues)
https://en.wikipedia.org/wiki/Perry_Rhodan
and the big headed guy in the picture is – as is the mousy looking one in the background – a good guy ..