From the campaign:
Now is a good time to announce our surprise for the 40k stretch goal Alpha alien! As soon as we hit our 40k stretch goal we are going to post an update to all of you asking what kind of creature you want the Kickstarter exclusive Alpha alien to be. This will be choosing by type. Examples being bug, reptile, demon, undead, humanoid, etc. You can also mention specific features you would like to see. We will let this run for a couple days and see what everyone comes up with and what you all like most. Once we have a choice we will have our artists working on the Kickstarter exclusive Alpha alien you guys helped design! We are really looking forward to this one!