My dogs (65 and 85lb Dobies) almost killed/drowned a cat up on the job in Mt Vernon last year.
I was staying in my trailer up on the job during the week and had the dogs with me. I let them out in the am to run around since the whole job is fenced (large lot with a huge house on it), and I hear them start barking. I go out to see what is going on and realize the have a cat up a tree in the middle of the lot.
I figure no worries, they will be getting put in the trailer in a bit and the cat will go on its way before they get back out for lunch, so I go back in the trailer to finish my breakfast. I also figured there was not a cat on the planet STUPID enough to come 30' down a tree with 150 lbs of Doberman sitting at the bottom. I WAS WRONG ! !
I no sooner get back in the trailer when all hell breaks loose outside. I go running back out to call off the dogs and all I can see is the big Dobie (Silas), in the retention pond with his head in the water and four cat feet sticking up out of the water. I get down there and call/pull him off and as soon as the cat pops to the surface the little Dobie (Lucy, the tripod), is on it and back under it goes ! !
After much yelling and getting them both by the collar I get them back up to the trailer and throw them in the back of the truck. I go back down to check on the cat figuring I'm gonna hve to get a shovel and the thing is still in the pond kinda hissing and spittin at me. I get a stick, which it attacks, and drag it out (coulda used a hockey stick at that point Dave).
I tell the cat it had better get the hell out of there by lunch cause the dogs are gonna be back. Later on I went to check on it and it was gone. .. ..
Stupid F'n cats.

And stlhead, yeah, feral barn cats are some nasty mo fo's. We used to have a kitty shoot on the farm every couple of years to control the population cause you couldn't (and wouldn't want to ) catch them to vacinate them. Not a varmit on the property though, besides the cats.