As the banner says, if you qualify, you can log it. All OCNA Challenge caches are locationless type, arranged as Geo-Art in The Gulf of Mexico.They are all "unknown" (?) caches, owned by a special Admin account, OCNAChallenges. Do you have an idea for one? Feel free to contact us.
Recommendations: Many people don't realize this, but The Geocaching.com Favorites Point system is copied exactly from The OpenCaching Network, with different terminology! Here, you receive one recommendation to give for every 10 caches found. They are relatively rare, as only 54 people have found at least 10 caches on OCNA as of the publication date of this challenge, and not everyone uses them all up. So to qualify for this challenge, you must have received a minimum of 3 recommendations on your owned caches.
Verification: For this challenge, you need do nothing really, except qualify, as your received recommendations is displayed in your profile. Keep in mind that for many other of our challenge caches, we do have the equivalent of a Groundspeak "my finds pocket query", and that .gpx file is easily imported into GSAK, or any similar stats program.