Is the old girl finally about to die? (Nx650)
 

As they say a picture is worth a 1000 words.

After I went to change the filter? Any ideas?

Not necessarily, I have seen a lot worse in sumps and filters of bikes that have lasted a lot longer, clean it out and if there is a gauze filter clean that as well, fresh oil and filter and ride it until something does go wrong which it probably won't.

its never nice to see but same as Mark, Ive seen worse, if you are not already using one, get a magnetic sump bolt fitted. You could remove the gear case cover and check for any more particles, obvious wear or a damaged clutch. Id probably do a couple of interim oil and filter changes and see if you are consistently getting that much material out over the next few thousand miles - if so then Id be a little more concerned and if you have a big trip coming up Id investigate further before you leave - or just keep riding :)