Yes that is gum on the wall! Capri suns, Ice cream wrapper, candy wappers even black electrical tape!
So this was what I found this morning behind the sofa. Xavier told me that he threw an empty caprisun back their so I moved the sofa and to my suprise he threw a bunch of other stuff, He even sold out his big brother!!! Yuck and I had just cleaned back thier last Sunday. Children!!! Gotta Love them!