[Windflier]

Even if she had used "creepy" it would be used in conjunction with "ass" Like "Bad" in badass, or "sorry" in "sorry ass..."

Exactly. It's a really old form of black slang, i.e.,

stupid ass
dumb ass
slow ass
punk ass

I grew up with that lingo, and recognized it instantly. Hell, it's not even 'black' lingo anymore.

[thecodont]

Yes, the suffix “ass” is used as an intensifier, and I’ve heard it used by non-blacks in other contexts.

Broke-ass Stuart
Big-ass biscuits
Spicy-ass noodles