Temporary insurance is sometimes granted in terms of a reminder to renew an existing insurance contract, and can be encountered in various other types of documents.
Oval and approximately 20 feet wide, they initially look like gigantic mirrors, but better resemble a pin-sharp video screen once encountered up close.
Whenever excrescences are encountered, an initiating and an exorcising amulet are placed over them, then they can no longer conceal or transform themselves.