Myth or wut? Blackbeard Never Sleeps
The reasonable assumption is that Blackbeard is a human and therefore he has to sleep at least some portion of the time or he would die, so this has always been an unclear thing to me - does he or does he not tuck himself in at night, some days?
This is based off of Shanks and Buggy discussing how Blackbeard didn't sleep at all during their encounter as kids. (I'm not sure either why people think that he simply never sleeps - he may have just not slept during that encounter).