Cats do the darndest things, and this particular cat has an unusual obsession with...the trash can.
Cats love small spaces, and they're full of curiosity. This often leads to cats "disappearing" in their own homes for hours on end. Who knows exactly where they go to, or what they do when we can't find them. In fact, cats probably get up to a lot more trouble than we're aware of. Just ask this cat about his trash can obsession.
This orange kitty is clearly driving his owner up the wall. But it's not his fault - he simply can't get enough of diving into the bathroom trash can. It doesn't seem like he's really after anything; instead, he seems to enjoy the small space it provides, and the challenge of jumping through the hole in the lid. Take a look at this silly guy.
Does your cat have a similar obsession, either with a trash can or something else that he really shouldn't be into? It can be difficult to convince cats to leave something alone once they've gotten the idea that they want it. Sometimes you can train a cat not to perform a behavior, like jumping into a trash can, but it takes vigilance and persistence, and there's no way to guarantee that the cat doesn't return to the behavior when you're not home.
A better option is to make it difficult or impossible for the cat to get into what he's trying to access. Put a solid lid on a trash can so that your cat can't easily get into it, or better yet, close off the room from the cat so that he can't get near the trash can. This is particularly important if your cat's behavior could put him in danger - imagine what might happen if your cat got into a trash can containing toxic substances or spoiled food.