Oh, I did not know about "Skulduggery Pleasant", that sounds funny!
Yes, Stephen King included a few references to the Harry Potter saga in his "The Dark Tower" series. This is the fragment:
"Check out the crate-lid," Jake said when they joined her.
Susannah had set it aside; Jake picked it up and was studying it with admiration. It showed the face of a smiling boy with a lightning-bolt scar on his forehead. He was wearing round glasses and brandishing what appeared to be a magician's wand at a floating sneetch. The words stenciled beneath the drawing read:
PROPERTY 449TH SQUADRON
24 "SNEETCHES"
HARRY POTTER MODEL
SERIAL #465-17-CC NDJKR
"Don't Mess with the 449!"
We'll Kick the "Slytherin" Out of You!