Flying feline

Our neighbors' cat has taken to launching itself at our kitchen window, where 15-year-old Mali defends her home turf. When they first got this cat, he came into the basement through our cat window, ignored our four resident hissing or cowering kitties, and marched up two flights to our bedroom. We mentioned it; they said it couldn't have been their cat because he was in the house all day. Uh-huh. This cat has distinctive polka-dot markings, though you can't see them in this picture of his underside.

Anyway, they started putting him on a leash...but then walking him through our yard and standing by while he sprayed our back door! Words were spoken. He stayed mostly indoors for years after that, until just the past couple of months. And now we have the hurtling-through-the-air window attacks. He walks up the steps, slips through the railing, and bang, he's all over the glass. Meanwhile, Mali--our only remaining four-footed family member--is hissing and yowling, and this often happens long before I was planning to wake up. Not to mention that I finally washed that window a few weeks ago and now it's totally smeared. I wasn't planning to do it again for...oh, say, a couple of years.

We've tried splashing water on the intruding cat, but he's not impressed. Now we've placed a pan of water where he lands, so he's been getting wet feet, which clearly annoys him. I think we should go for something a little deeper. No desire to hurt him, but we'd sure like him to stop hurling himself at us.

Ever seen anything like this?