You want a ghostly head peering down ? Throwing some possibilities in.
1. Instead of a layer mask (which I generally go for) that head image works quite well with color-to-alpha. Interesting shapes. (if required layer -> Transparency -> Add Alpha Channel ) Colors -> Color-to-Alpha Do not worry about the checker pattern.
2. Into the background image with it. Set a 50% layer opacity.
3. A "ghostly" possibility is C2G `Colors -> Desaturate -> Color to Gray.
4. Eyes and head into a layer group. Eyes separate on their own layer. Play with color curves to brighten (make staring eyes).
5. With a layer group you can transform the contents as one. Used the 3D transform change 'looking down angle' (not sure I am happy with that) .
Anyway some thoughts for you to consider.
1. Instead of a layer mask (which I generally go for) that head image works quite well with color-to-alpha. Interesting shapes. (if required layer -> Transparency -> Add Alpha Channel ) Colors -> Color-to-Alpha Do not worry about the checker pattern.
2. Into the background image with it. Set a 50% layer opacity.
3. A "ghostly" possibility is C2G `Colors -> Desaturate -> Color to Gray.
4. Eyes and head into a layer group. Eyes separate on their own layer. Play with color curves to brighten (make staring eyes).
5. With a layer group you can transform the contents as one. Used the 3D transform change 'looking down angle' (not sure I am happy with that) .
Anyway some thoughts for you to consider.