The Hither-Thither Staff as seen in Dungeons and Dragons: Honor Among Thieves has been created for use in your game. Other than recreating the events in the movie, what can you do with it? This magical item is actually very capable in combat and exploration.
The Staff in Combat
Assuming combat takes place in a space with high, smooth walls or ceilings, the staff can be effective in combat. Use the first charge to create a portal high up on one of these walls or ceilings, and the remaining charges to create portals under enemies. Let your high-strength players get in on the action by throwing the baddies through the portal as well.
Depending on the intelligence/wisdom of your foes, consider giving them a dexterity saving throw to attempt to prevent themselves from falling through the portal. One way to increase the interactivity of this would be to set the DC and then say that, on a fail, the creature has grabbed on to the edge of the portal, but now grants advantage on attacks and has disadvantage on its own attacks, as well as on strength and dexterity saving throws. If the saving throw is failed by 5 or more, then the monster falls and take a nasty bit of fall damage.
The Hither and Thither staff is also useful for creating protected high ground for ranged attackers in the party. Find a high, smooth surface and make a portal connecting it to a protected location where your wizard can be safe while they fire off spells at the baddies. This might be tricky in an unexpected battle, but could be one of the ways that a party plans to overcomes a BBEG.
A Hither-Tither Catapult
Consider weaponizing the portals themselves. As momentum is conserved between the portals (as demonstrated in the movie), they can be used as part of a magical catapult. Putting a portal at the bottom of a cliff or other elevated platform and dropping stuff through it causes falling objects to be launched forward out of the other portal when it is on a vertical surface. Using this as a weapon may take a little coordination. You may need your barbarian to draw a monster to a specific location on the map to target them. It would aslo come in handy if you’re players are helping end a siege. They may have stationary target they can carefully dial in the proper velocity and positioning to hit.
The Hither-Thither Staff in Exploration and Puzzle-Solving
As we see in the movie, the staff is convenient for surmounting physical obstacles, such as rivers of lava. Check out the Portal game series for ideas on how to make traversal puzzles for this item. The players only have 4 charges to work with, though. This gives them a way to shortcut physical barriers. It also lets them get stuck in locations they can’t easily return from without another use of the staff. What happens when you have to spend the night waiting for the staff to recharge in a dank catacomb? You might have to get creative, and risky, about overcoming obstacles. You might also make some new friends. The biting kind of friends.
These portals are also good for moving heavy objects from one place to another. You can portal heavy statues moved onto pressure plates. Locked treasure chest can be dropped from the ceiling to free up the (hopefully) durable contents.
Lastly, why not show a little forethought and set up a portal that can get you back to the outside of the dungeon? Set one up before you enter, and when things get a little to heated, pop another portal for your escape. I just hope that whoever finds that portal and decides to wait for you to come through is friendly. Or worse yet, what if that portal let you escape, but also frees whatever benighted horror was chasing you?
That’s a pretty great magical item. How about some great stat blocks to go with it?