Worst thing I heard today

We are preparing to put our house on the market within the next six months to a year, so the process of decluttering and boosting the functionality of the space available is in full swing. Mostly out of necessity as we have 3 kids who seem to collect crap by the minute, and a 3 bedroom home which I KNOW is fine, but we definitely have some needs that our home doesn't provide anymore.

My grandmother is currently visiting and since the weather was shitty, I "suggested" to my husband that we execute my new furniture- and toy-moving plans, so we rearranged the (finished) basement and brought down a lot of the kid's toys. We have moved toys to and from the basement several times a year, each year, always changing our minds about where we want the stupid train table to be or where it makes the most sense to have the kids play. Our home office (computer, printer, bookcase) is also down there, as well as an extra bed, the husband's makeshift man cave (a futon and surround sound), and the cat's electric litter tray. What is not down here is a bathroom. 

Our oldest son often comes down here to play games on the computer or Xbox. Completely unregulated. 

In the middle of all this excitement, he says, "Sometimes when I'm down here and I need to pee, I just pee in the cat tray."

What the what? We all just looked at him the way you would look at a parent who just gave their kid a snack after taking them to the porta john. Just me? Really, you don't think thats gross? Even with a hand sanitizer bath? You nasty.

It was almost like he didn't get why we were all "WTF?" With his hands spread and shoulders shrugged, he reassures us that "I don't step in it. I just pee in it."

Every important parenting moment that I had up to that moment started flipping through my head like a rolodex, looking for the card that said "tell son not to piss in cat's litter tray." Guess what Internet? It wasn't there. 

I lost at parenting today.