Blood on the Knife and the Eyes
The first an most obvious indicator that a Ghost Face Pop! is fake is by the bloody knife. On a real Ghost Face there is blood splatter on the entire sharp edge of the knife. If you have a fake, it looks like the knife was dipped in a bucket of paint.
You can also tell a fake by the eyes, as with many fakes. A fake is going to have a very flat finish and usually stop before the edge of the eye socket. The authentic Ghost Face is going to be glossy and look more finished.
Errors on the Box
The next best way that you can distinguish a real Ghost Face from a fake is by looking at the Funko Pop! logo on the front of the box. On the fake Ghost Face the color red where the logo says “Movies” is going to be much darker on the fake than on the authentic version. You can also tell a difference in the font on the word “Movies”.
You can also look at the actual work “Pop!”. If yours is a fake you will just have a gradient from yellow to orange. On the authentic it will have a yellow and orange half-tone coloring.