There are three options for Body Type which define the behavior of the Rigidbody 2D. Any Collider 2D attached to that Rigidbody 2D inherits the Rigidbody 2D’s Body Type as well.
The selected Body Type defines the Rigidbody 2D’s movement behavior (position and rotation) and Collider interactions. When a Body Type changes, Unity recalculates various mass-related internal properties, and all existing contacts for the Collider 2Ds attached to the Rigidbody 2D need to be re-evaluated during the GameObject’s next FixedUpdate. Depending on how many contacts and Collider 2Ds are attached to the body, changing the Body Type can cause variations in performance.
The properties of the Rigidbody 2D component in its Inspector window differs depending on which Body Type you have selected.