He said that it was wood burned but it looks like decals done to it. I use a technique of using a type of boat sticker as a stencil and hit it 120 aluminum oxide in my media blasting cabinet on gun stocks and it makes an insane looking frost style fade out of the stencil. My teacher who taught me how to do it and came up with the technique, does it on his long range competition rifle's gun stocks. He did a pile of skulls on the side where the grain opened up in the wood so it looked like they were coming out of the wood and it looks amazing. He is also an amazing bassist. He played bass for a famous 70's - 80's band but went on to become one of the top rifle builders in the world and a hall of fame long distance competition shooter. I am blessed to have him as a teacher and friend.