Some GSD's do strange things.
Lisl removed the shoe laces from my running shoes twice and from a pair of casual shoes once. Didn't chew on the shoes, she just removed and chewed the laces.
Strangest behavior I've ever seen. She hasn't done it again since she was around six months.
Bear, Anna, Molly, Ossie, and The Countess Lisl von Schlaf
An Unhappy German is a Sour Kraut!