Not sure if this helps, but I recently learned about viroids in my bio classes. From what I've gathered, viroids are basically just sequences of genetic material that can have virus-like effects. Most viroids don't have a shell (Envelope or capsid) like most viruses do, and they have far fewer genes. I believe that most viroids consists of just a few hundred base pairs. What's intriguing to me is that viroids don't actually code for anything. I think maybe some viroids code for one protein, but that's about it. Despite this, viroids can still wreak havoc on an organism. It's difficult to determine whether or not viroids are living things or organisms, but I think there is definitely some function there as you put it.