Minecraft wiki entry for Development, associated text: Additions
Creepers
Did not have a proper texture yet and used a placeholder static texture
Was passive (?)
Did not explode when killed
Oddly, in the HTML for the original 2009 Survival Test webpage, "Minecraft creeper test" is mentioned. It is possible this build was uploaded at one point for private testing.
1. August 20, 2009 IRC logs (P12:16:45 <08Notch> http://www.minecraft.net/temp/disturbingpig.jpg)