The Cursed Torc
For this idea, I was thinking about cursed items and that it might be interesting to create one that could be useful to a player. After all, if you know a cursed item’s secrets, it could still be useful, you just have to use it differently. After all, the most useful items at a DM’s disposal are things that have multiple applications in a story. Why should the DM have all the fun? This item could give a player the opportunity to mess with the NPCs a little bit. Adjust values for this item as appropriate to your game system and the quest level you’re playing at.
The Memory Prison was an idea that I intended as more of a role playable experience rather than anything else. It isn’t a physically dangerous trap. Nevertheless, it can pose serious peril depending on how the DM decides to implement it.
One of my favorite things to do when creating magical items is to take a familiar item out of the source books and re-purpose it while leaving the original function intact. The Immovable Sword in this case is exactly what it sounds like: a sword that also functions just like an immovable rod! Fun!