It’s rare to find something truly rare and amazing in medical literature. But the idea that researchers could transplant a tadpole pineal gland and have it turn into a normal eye counts as one of the oddest things I’ve read recently. Adding Vitamin A helped it grow, but the idea that a gland could become an eyeball is pretty bizarre. (More here).
When you look farther, the pineal gland is responsible for creating an inner rhythm in the absence of light. That makes it responsible for the basic rhythms of our lives, including our immune responses. Not bad for a little gland that had pretty much been written off as incidental.