Deprivation Field

You create an invisible forcefield around a building of your choice, which allows entry only to an individual with the possession of a silver key that has been casted with the spell, as well as any other creatures only if the door to said place is unlocked. The forcefield is noticeable to any creature and they recognize it as harmful. Any creature trying to forcefully enter the locked building without a a key will suffer complete sensory deprivation, that will lead it to confusion and unintentional self-harming behavior, which can lead to death. This effect will stay up to d6 minutes after the creature is taken out of the range of the forcefield. During that time the creature is prone and will not be aware of it's soundings at all, but will be able to receive magical messages such as message or sending.

Another key can be created by the caster, which allows more people with it's possession to accesses the building unharmed. To do that a similar ritual in the length of 10 minutes must be casted within the field, providing another silver key. It is very challenging yet possible to navigate through the space, even with complete sensory deprivation. It can be achieved with the aid of a divine being or an additional magical outside sense such as magical blind sight or true sight. 

The spell can be maintained by recasting it at same location location every day. If the spell is maintained for a full year it becomes permanent, and the gemstone is absorbed by the horn. The spell will end if the horn is destroyed or taken out of the field's range.