A player in my campaign plays a mystical Unearthed Arcana V3 and uses the Phasing Eye ability. I've tried to find a way to reduce its use a little.
Most of the time, this is not a problem and is used to spying behind the scenes or containers. As for the dungeons, Phasing Eye is first sent throughout the complex and there are not many ways to keep some areas inaccessible. I do not have a problem with giving the player a chance to track, that's what the ability was designed to do after all, but it still raises some issues.
- Time: Screening can take a long time. The party is encouraged to send the eye through the entire dungeon, to map as and then to retread the area itself.
- Drama: When the whole dungeon is open to reading, it is difficult to set up ambushes, traps or dramatic revelations.
- DM flexibility: Giving the dungeon layout and the enemy's position means that things can not be changed on the fly to improve the game. The encounters can not be moved behind the curtain and it can be strange to have to imagine an explanation of what a monster could do in his spare time.
Arcane Eye is similar but can be controlled by well-placed physical barriers. As I understand Phasing Eye, nothing less than 30 feet. Thick wall can hinder its movement.
Mordenkainen's Private Sanctum, as it is written, only blocks divination spells. I think it's reasonable enough for him to also block Phasing Eye, but I prefer to use it sparingly because all dungeons do not make sense for the spell to be effective.
I've planned to add nomadic guards who can see the invisibility, but even if they see the sensor (I do not know if they could or not), they could not destroy it or dispel it. The best that they could do would be to give the alarm that an amorphous glowing object was seen floating.
Are there alternatives to limit the use of capacity or can changes be made to the design of the dungeon to better adapt it?