The Big Cat - The Largest Black Cat

i saw a big black object walking o l fours. The object looked similar to a cat with a very long black tail. By the time i noticed him trotting kind of on all fours off down under some brush into wooded area. This was the largest black cat type animal i have ever seen. I also live in a city, so it's very rare that t we have such or a large cat in that area.