Where is it?

Here he is, chewing up the devil's horns. His own are apparently hidden.

I know he had a little accident in the house. I found the mat in my laundry room as a little wet, so I washed that, but it still smells. Where is it? I can't find another spot anywhere.

I am going to have to get rid of that mat. Apparently, no matter how many times I wash the smell out, he still thinks it is ok to use it as a restroom. I just wish I could figure out where else!