I am aware that for most of your life, before you came to the shelter and then to us, you were an intact Thomas Cattus. I don't know what might have triggered this sudden behaviour change - a run in with a fox or other cat seems unlikely since you have had plenty of those before. I'm not even sure it was you.
However, for the first time since you cats moved in, someone decided to mark their territory by spraying in the lounge. It was not your staff (we're clutching our noses). Matilda lives upstairs, and won't go near the affected room. You will, and look very proud of yourself. The circumstantial evidence is strong.
I have never smelt anything like this in my life, and the room is a chemical warfare zone right now. Yes, your staff are going over it with a UV light and white vinegar and odour repellants...and gas masks and watering eyes.
If you ever do this again, I will apply a cork to the relevant regions.
Your loving staff (with clothes pegs on their noses)
P.S. Any hints or tip on killing the smell would be very welcome.