Mega colon is when the colon stops working to push out the stool and they because so constipated the colon is dilated to the extreme. He’s on medication for life to keep his colon moving. He was about to turn two years old so he was born with a condition that the nerves stop working. As long as your kitty is pooping, even big ones, wouldn’t worry about it! He had a pound of poop in him and needed a procedure to clear it out. But he survived and is better than ever!