Some cats (usually female, but not always) will bring you "prey" they have caught. Instinctively, mother cat will bring her kittens prey; first dead to introduce them to solid food, and later live to teach them to hunt. Indoor cats don't know how to hunt, or that small animals are food, but sometimes the instinct kicks in anyway. The "prey" they hunt is toys, so that's what they bring you. Either they're proud of their hunting prowes, or they think you need food. I have a friend who has a cat that brings in live birds from the back yard and leaves them for her to find. By then shock has worn off and the bird is flying around the house and she has to catch it to get it back outside. So when your cat leaves toys in his food dish, He's bringing "prey" back to his "den", and when he leaves toys in your shoes, he's leaving you "food" where he knows you will find it. My cats love those real fur mice and will do the whole toss-it-in-the-air-and-kill-it routine with them. Because I live in a 100+ year old house that mice get into, I buy the cats the brightly colored ones so I can tell at a glance just WHAT they're playing with!
