First I selected the skull with the path tool and created new layer from cut. Then I liquifed the skull, to get the kindof angry look. Then, I desatured the skull and blacked out the eyes using "Levels".
step 2 of 6
Then I pasted the texture in a layer on top of the skull and put that layer to Overlay, played with opacity and created clipping mask. I also painted the teeth of the skull black in an overlay layer. See the source link for the texture
Then I painted the eyes in. Two red spots, erased a bit of, applied outer glow and Bevel and Emboss. I also drew the glow around the eyes, in an overlay layer with a red brush.
step 4 of 6
Then there was the tentacle. Made by making a selection and filling with black, then same selection on new layer fill with white. Then blur the white layer, you get a glow effect. Then distorting, applying Shear. drwaing blood on it, sharpening and applying Plastic Wrap.
step 5 of 6
Making another tentacle the same way and adding the glowie things, made with paths and stroked. The new tentacle is a bit sloppy because of blur and painting with black to create some sort of fading.
step 6 of 6
The background is made of clouds, difference clouds. Then motion blurred a whole lot and then distorted. THen applied Glowing edges, which came out f*cking awesome! For the light behind the skull, that was made using a white brush and painting some spots and one big spot in the middle, and radial blurring it (zoom) and putting the opacity to around 30. We're done !