Required Wild Shape Mastery, Wild Shape High Mastery,  Must be a druid, and must be a subclass that is based on wildshape, like a circle of the moon druid.

Only selectable by druids, and they must be druids of the moon (or other wild shape based subclasses, or if DM allows it otherwise)

The druid has mastered their wild shape ability beyond that of normal druids and gain the following.

• The character's wildshape ability now lasts indefinitely, until the druid changes, or till their form reaches 0 HP.
• The CR rating in which the character can take shape is increased by an addition 2 (cumulative with previous mastery feats) but this can not exceed the level in the druid class.
• The character can now communicate via telepathy with anyone within 30' that they can see, the recipient must understand a language that the character knows and can reply to them as normal while the link is held, it takes an action to start a link, and a bonus action to end one.
• The characters wild shape is no longer limited to beasts but has to be a natural creature with the exception of Monstrosities, so no undead, constructs, or aberrations,  they can take on the form of anything within limitations they have seen before. ((Of course this is with DM consent on what you can or can't change into.))
• The Character gains 1 to an ability of their choice.