This version of Unity is unsupported.
Removed

Component.rigidbody2D

Obsolete Property rigidbody2D has been deprecated. Use GetComponent<Rigidbody2D>() instead. public Component rigidbody2D;

Description

The Rigidbody2D that is attached to the Component's GameObject.

This property will be null if no Rigidbody2D is attached.

See Also: rigidbody.