A nicely put word than Pack Rat.
These people tend to collect soo much stuff, whether it be diapers, books, poop, shoes, clothes, or hair samples that it gets very over bearing and the items in turn tend to run their life to where they don't know what to do with themselves.
Gary: Hey, i'm over behind the stack of newspapers and to the left of last nights food collection.
Boy: Dang Girl! How many shoes do you have up in this closet?
Girl: Oh I only have12 here, you should see my garage, I have about 300 there, but don't worry they are all in boxes.
Boy: Girl you're a hoarder of shoes.
Ralph: *flips to Hoarders episode*
Mother: Oh my word! Well, Ralph, I suppose I ought to be thanking my lucky stars you room doesn't look like THAT.