This staff, about seven feet tall, is made of gnarled ancient wood. Embedded in the tip is what appears to be a miniature castle tower, made of stone. The tower is fully crenelated and even has a few small windows spaced around it; though there is apparently an interior to the tower, it is completely impossible to see within. It is unclear what caused the tower to be embedded in the staff.

Possibilities:

1. When you invoke the staff properly, a darkness grows within the windowed space and you then have power of destruction over castle and other stone fortifications: causing walls to crumble, towers to fall, etc.
2. When you invoke it properly, it gives you power of persuasion over castle staff: guards may be more willing to cast a blind eye, cellarers become more generous with their stores, etc.
3. There is an open space in the middle of the castle ‘roof’. The space just fits an orange crystal found a few miles away from the staff. When you fit the two together properly, they grow into a very tall signal tower. You can scale to the tower’s top, where an immense signal fire burns; and if you are the one who fit the two pieces together, you can command the fire to send out various signals.
4. When you use the correct keywords, the castle can be removed from the staff. If placed in the right locale, the residents of the castle will exit and identify themselves: they are the Ladies and Lords of Elf-Land, imprisoned within the castle for a thousand years.
5. Though the differences are subtle, each crenelation of the castle is a different height. The castle is in fact a key; when you turn the castle in the correct series of circular notches, the lock will open.
6. When planted firmly in the ground, an amber-colored wave of energy will emerge from the castle and surround you and all your allies in a near-impregnable field of magic.
7. When you firmly plant the staff into the ground several times along your course of travel and then say the correct invocation, a string of guard towers connected by a stout stone wall will spring into place.
8. When you invoke it properly, the roof of the castle will detach, giving access to the precious items contained within.
9. The staff is modeled after a real place, where a tower is embedded in the top branches of a tree. Someone is imprisoned within the tower, and can’t get out. They plead with you to break the staff and free them.
10. If you tap the staff three times on the base of a massive tree, a stone fortification will grow from the crown of the tree.
11. Invoking the staff correctly will create one medium-size stone structure: a bridge, a house, a cairn, a mausoleum, etc. — in fact, anything except a fortification. The structure will continue to exist until you create a different structure with the staff.
12. There is precisely one tower in the whole world that looks exactly like the miniature in the staff. When tapped on the ground, the staff will violently bring that tower (and all its contents, and occasionally some of the supporting structure) to the spot tapped. Keep hold of the staff, lest someone else bring ‘your’ tower to them…