If you need simply skull drawing you can call me,, I would offer you simply skull in line sketch. Creepy or funny it's up to your pleasure,, if you have some references you can show me, and I will draw in it style. Or, you give it all to me.
Okay,, now let me explain what I offer. I will draw skull sketch on paper Black and white not full color Paper size A4 scanned in 800dpi
Once review for revision when sketch line ready, before inking. I don't work with AI. If you need source file it will be on PSD.