During setup, a nasty SL bug transferred items from your inventory folder into the Yellow Ball.

If you are using HUD v5.4.0 and above, the Yellow Ball will do these:

• it will retain all no-copy objects (since these are the ones that are moved from your inventory, and risk being lost).
• it will retain all non-objects (e.g. notecards, animations, scripts etc.)
• it will not attempt to return any inventory to you (since this will put the inventory into the same folder that the bug is affecting, possibly resulting in an infinite loop).
• it will delete all duplicated copiable objects (since the original objects will still remain in your inventory, hence they are not lost).
• it will remain on the sim after the setup is over, so that you can retrieve any remaining items that might have moved.

To retrieve your nocopy items:

1. Rightclick the Yellow ball, and click "Edit".
2. Click the "Contents" tab.
3. Wait for the contents to load. If there are a lot of items, it might take some time to load. Once loaded, you can simply drag and drop any item of yours back into your inventory. You can also take the Ball into inventory and retrieve your items later.
4. After retrieving your items, you can safely delete the Yellow Ball.

If the contents tab has loaded and you do not see any items inside (other than the "LULU.setupBall.lsl" script), it means that none of the items transferred over were no-copy.