When play is pressed, editor either crashes or spams error messages

When it doesn’t crash, the error message is saying that my Rigidbody is not assigned to an instance of an object. Here is how I am trying to assign it.
protected Rigidbody enemyRb;
void Start()
{
enemyRb = gameObject.GetComponent();
}
This is in the parent class, while the child classes are the scripts attached to my objects containing the rigidbody components, if that is an issue, then how would I get my rigidbody component reference from my child class to the parent for methods? When I try to pass it as a parameter I get an error message this it is being initialized more than once, and that that is not supported. I could just move all the methods from my parent class into my child classes, but the lesson I’m on is literally to showcase encapsulation and polymorphism. Any help would be greatly appreciated.

Doubtful the above line is causing the crash. Post the full script of the parent class for us to look at. Most likely you have an infinite loop going on.