My cat is 13, a house cat all his days, we got him about 8 years ago after his previous owner died.
He used to eat only Royal Canin wet food as allergic (skin scabs +++) to any cat food from supermarkets etc
I changed about 5 or 6 weeks ago to Katkins which after a few weeks of soft stools, he is doing great with - more energy and softer fur, no constipation (after being constipated a lot on RC)
I think he has a UTI in the past few days as licking his bits and not happy going to wee. He has been better yesterday and today with weeing.
But he just chucked this up in front of me and if I hadn't seen him do it I would have thought it was a poo 
Do I need to see if a vet will see him or watch and wait? He seems okay now, sitting on me purring