A Chibi-style Steve hat available when you download the Ichun's Hat Mod, which is obtainable by killing an animal that spawns with the hat
Credits to Lostminer for the head
Thanks @Derpysquidman50 for telling me the real mod this is from.
1. Click on the papercraft design image.
2. Make sure it has not been resized by your browser (you might need to click the image again).
3. Print using your browser's Print function.