I had a jack Russell, helluva dog, would go to ground in a heartbeat, hated cats. Spied next doors cat under my shed, flushed it out chased it and then followed it at 100mph through the cat flap! My dog chased the cat round the bungalow crashing over furniture and trashing ornaments, the cat climbed the curtains and so did the dog! He finally nailed it in the bathroom. The cat lived, the dog didn't see what all the fuss was about, I had to pay the neighbours insurance claim for the damage, they never spoke to us again and moved out shortly after!
RIP Barney....legend.