Spoiler protection in threads

How about this, a new tag or, just option when making a thread that makes it invisible or blocks out a section to people who haven't completed that challenge.

I understand this would need a lot of extra sql queries which hbh stuggles with already, but it would be very useful, there must be another way?

Suggested before, several times as far as I know, by myself as well. I've already supplied my thoughts on it here: http://www.hellboundhackers.org/forum/viewthread.php?forum_id=19&thread_id=15142#post_140757

sorry for the dupe.

It is a duplicate from numerous of other people, although there's no need for any other SQL queries. Just replacing the tag with a div box and som Javascript code that toggles display ? block : none, like when you click on a username in the shoutbox.