Big furry fuzzy kittens ( or big furry fuzzy kittens with claws) is a phrase said when someone is more then mad. If they say big furry fuzzy kittens with claws, then they are beyond mad and are so upset they have blacked out.
Person 1- telling story or comment making other person mad.
"You got to give that mad dog of yours somethin'for Xmas to quieten him down. I read the local petshop's got an offer on A Basket Full of Fuzzy Kittens for $10.99"