If a creature leaves the battlefield and returns, Nadu's ability "resets" on that creature, allowing them to keep benefitting from it if they become the target of a spell or ability
All the sea creatures make it a great set for biology nerds too
It's the de facto best commander for its respective creature types in Commander, and that's before you even factor in the back half
To take full advantage of the +3/+0 buff, putting this on a creature with vigilance is a good plan
In addition to Hall of the Storm Giants, Crawling Barrens, the sixth man-land in Standard could see play in control strategies, as it benefits from decks with lots of mana at their disposal in the late game
Including this article, as it happens