When you finally realize, how bad things really are…
It doesn't represent the pineal gland. The catholics do not believe in any of that chakra 3rd eye new age stuff. They represent arks. Like noah's ark. The ark of man. They signify we were placed here by intelligent design. They know the truth. They hide it from you. They do not believe you can handle the truth, besides, what would happen right away if we destroy God. Is that the kind of world you'd want to live in?
The pineal glands only function is to produce melotonin to keep you balanced and able to sleep.