The Druid’s Wild Shape ability is one of the coolest abilities of any class. Get into some trouble – and in a flash turn into a fly and buzz away. Or somebody comes after you and whoosh! A grizzly.

If a character chooses Circle of the Moon, they get access to higher level beast shapes – AS well as the ability to turn into an air/water/earth/fire elemental. 

Yep. A player or an NPC the DM controls can burst into an elemental at the drop of a hat. Each elemental has immunities and resistances – which that character now gets! Characters also get all of the Hit Points of their new shape. Booyah!