Padlock

It will randomly appear in various places where a padlock can be hung and block the path. Once someone is blocked by it, the padlock will permanently lock that person. It will appear wherever that person goes, as long as there is a place to hang a padlock and it can block their path. However, the key will appear nearby. The rules are invalid: it cannot be killed, cannot be harmed, cannot be sealed, cannot have its soul erased, cannot be modified, destroyed, or erased. It never gets tired, so it can only be opened with a key, locking a person until they gradually get used to it, then the lock will be released, and it will search for the next target.