You can increase your size by 20ft times your AN.  How you are able to do this is your choice.  You can maintain your size for free, and revert to normal at will for free.

When you grow, you gain 1 Strength and 1 Durability for every 20ft of growth.  You also get 1 extra Strength for your first stone of growth.

This Action can not be improved by lines.

Rules for Action Box:

• Grow to (AN x 20ft)

• Cost to grow:  1 stone/20ft

• +1 Strength/20ft (+1 extra Strength for first 20ft)

• +1 Durability/20ft

• Duration at will

• Can't be improved by lines