My friends cat once dragged a nice joint of roast beef through the cat flap. Next door had put it on the side to rest one Sunday lunchtime and made the mistake of leaving the kitchen door open 
A friend's cat once managed a roast leg of lamb over a six foot fence as a gift for his hoomins. This was the same cat that delivered a jam roly-poly to my friend's bed in the middle of the night. I keep trying to explain this to my mogs, but all I get are voles. 
I too have shared a house with a cat who has brought home someone's Sunday lunch. In this case an entire, and still piping hot, chicken. At the time I lived in a house as a student lodger to a young couple. the "cat flap" was the lower part of a sash window which for resons known only to the kitchen installer, could be opened to expose 6" of the kitchen cupboard under the sink. I came out of my room because I could hear a trememndous banging coming from under the sink.
I assumed that the cat was having yet another cat fight in the cupboard, but couldn't hear another cat.
I opened the door to find the cat trying to pull the roast chicken in through a gap about 2" too small and knocking over all the bottles and cleaning stuff in the cupboard.
We never did find out who it belonged to.
