We've got three cats. Two older boys of 13, Fat Cat and Skinny Cat (identical apart from weight) and one kitten who is around a year old.
Fat Cat was the laziest cat in the world. Will hunt a bird in the garden, but usually gives up on the basis that it's too far away. Loves following a cat toy with his eyes/head, but unless he can reach out for it form his current position he'll not move. The only time he exerts effort is when he's opening doors, which he does by getting skinny cat to press on the door while he jumps and batters the handle down.
He's got a miaow that suggests he is absolutely starving. Morning and night when he's fed you'd think he'd never been fed before. He piled on a tremendous amount of weight two years ago, then started vomiting daily and being picky with food. it took four vet visits and a co-incidental meeting with an elderly lady along the road before I discovered that my 'starving' cat was being fed by her THREE times a day. After that I made a few enquiries and discovered that the £400 worth of tests were unnecessary because the greedy cat was getting fed in FIVE houses that I know of.
Last year a neighbour found a tiny kitten in our street. We searched for it's owner, put posters up in streets, in the vets etc, but we came to the conclusion she was dumped. She was only about 4 weeks old. We took her in and I hand fed her for a while. She was properly tiny.
When she was about 8 weeks old I got up in the morning and Fat Cat had managed to get the spare room door open. To my horror he had her in his mouth and was trotting along the hall with her. I ran after him only to see him dump her in his litter tray. I don't know why, and the vet thinks its hilarious, but he seemed to think she was his kitten.
She copies his pitiful miaow at food time. And he now thinks he's a fucking kitten and tears around the house like she does, including one amusing time when the kitten jumped from the sofa onto DH's belly and was then followed by 7kg Fat Cat :)
We lost Skinny Cat about 4 months ago. He has now trained the kitten to press on the door when he bats the handle so we're back to not being able to shut them out of the living room at any point again.