Shredding like crazy

(That's SHREDding, not SHEDding.) One of Lily's things that she does is secretly get into the bathroom while we're not looking, and shreds the toilet paper to bits. I'm not sure why she does this. Maybe she likes the rolling motion of the toilet paper or just the naughtiness of it. A lot of times we don't discover it until too late. I try to salvage the TP and use it (is that gross?), but it is NOT easy!