Design pattern to allow attaching one class to another

I am designing an RPG and would like to have the ability to attach classes to each other. What I'm looking to do is have say an Item class. The weapon class would inherit from it. A sword would be an instance of the weapon class. I want to then be able to attach properties to the sword. These properties would be other classes. For example I could attach the container class to it and the sword (only that instance of the sword) would become a container. I could also maybe attach something like an enchantment to that sword.

For a bonus it would be nice to be able to combine instances as well. So instead of having to have a fire_enchantment class I could just make it an instance of Enchantment and attach it to the sword instance.

I've googled around and haven't been able to find a design pattern that fits this. I recall studying one but can't remember what it was called (Was a few years ago)

I'm at a loss of of which design pattern allowed this. The combining of multiple classes dynamically.