Circle of the Hollow

Druids of the Hollow concern themselves with learning to see the world through the eyes of the creatures around them, both great and small. Far more experiential than academic, Druids of the Hollow try to learn exactly what it is like to live life as a bear or a squirrel, etc. Their focused studies allow them to take on forms that are normally out of reach to the vast majority of their brethren. This knowledge comes at a price, as Druids of the Hollow must sacrifice their most powerful magical abilities to take on these greater forms. 

Greater Wild Shape

Your dedication to studying the beasts of the wild allows you to take on a Greater Wild Shape. Starting at 2nd level, you gain the Greater Wild Shape feature which functions identically to the basic Wild Shape feature, with the following exceptions:

• You must expend a spell slot to assume a Greater Wild Shape.
• The CR of the creature whose shape you assume must be less than the level of the spell slot you expend.
• You have half the HP of the selected creature.

This ability does not alter or affect normal Wild Shape usage.

Any time you cast a leveled spell, except Shapechange or Alter Self, you must upcast it by 1 additional level with no added benefit from the upcast.

Combat Wild Shape

At 3rd level, you gain the ability to use Greater Wild Shape on your turn as a bonus action, rather than as an action.

Additionally, while you are transformed by Greater Wild Shape, you can use a bonus action to expend one spell slot to regain 1d10 hit points per level of the spell slot expended.

Primal Strike

Starting at 6th level, your attacks in Greater Wild Shape form count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage. 

Elemental Wild Shape

At 10th level, the CR of your selected beast for Greater Wild Shape may be equal to the level of the spell slot you expend.

Additionally, when you use a spell slot of 5th level or higher to take on a Greater Wild Shape, you may choose to take on an elemental form instead, whose CR is exactly equal to the spell slot used. Any weapons listed or implied in the elemental's stat block are manifested as functionally equivalent appendages and counted as natural weapons.

Shrewd Savagery

By 14th level, you understand the lives of the creatures you imitate better than they do themselves. Your insight is seen in your restraint, as well as your savagery. When you make an attack with a Greater Wild Shape form you may add your wisdom modifier to either the attack roll or the damage roll, but you must choose which before either roll is made.