Only one smell worse than a mouse piss mess made in your truck/boat/man cave/ recliner, and that is a poisoned dead mouse rotting away inside in an inaccessible area. I had a poisoned mouse die inside a sheet rock wall. Smelled terrible. Every time the humidity got about 50% the smell would come back. Finally filled the wall cavity with expanding foam to entomb the smell. I run a trap line now because I want to be able to retrieve their sorry carcasses.