Figured it out!!
So I couldn't for the life of me remember where or why the first voice that Grace tried for Rocky was familiar.
The deep voice that Rocky didn't like and even said, "Don't like, very scary." Or something like that kept nagging at me because I knew it from someplace.
Admittedly I am an anime fan and have been for most of my life. Ever since a relative showed me Akira I've been a fan and even before that really. So going back over Naruto Shippuden today it came on in all its English dubbed wonder and scariness.
It's the Nine-Tailed Fox when it speaks in the English dub version! So I don't know if anyone else was wondering that but that's what I found out today. I'm not sure if they actually used Paul St. Peter, who is credited as doing the voice, but it's spot on.