It's a mailbox, of course!
I'm just waiting for the note on our front door: "Sorry, but we can no longer deliver your mail to your home. Your mailbox seems to have been eaten by an extremely aggressive vine."
I really should trim this back, but it's so beautiful that I just can't! The gardeners came today and even THEY left it alone. And I've historically had a very bad time with gardeners and morning glories. The don't like them, and every time I plant them they do their best to destroy them and make it look like an accident.