Unsure why I am getting errors

This function is currently giving me 2 errors,

Assets/Scripts/poopingDog.js(78,34): BCE0022: Cannot convert 'UnityEngine.Vector3' to 'System.Type'.

Assets/Scripts/poopingDog.js(85,50): BCE0017: The best overload for the method 'UnityEngine.Vector3.MoveTowards(UnityEngine.Vector3, UnityEngine.Vector3, float)' is not compatible with the argument list '(UnityEngine.Vector3, System.Type, float)'.

But to me it all seems to be correct? What am I doing wrong here?

 function Spawn ()
 {
     animation.Play("Spawn");
     yield WaitForSeconds (.8);
     animation.Play("Pooping");
     yield WaitForSeconds (poopLength);
     animation.Play("PoopToRun");
     
     var targetPosition = Vector3;
     targetPosition =  Vector3(transform.position.x - 1, transform.position.y, transform.position.z );
     
     var t:         float = 0.0f;
     
     while(t < 1)
     {
           t += Time.deltaTime / 2.0;
            transform.position = Vector3.MoveTowards (transform.position, targetPosition, t);
            yield;
     }
     
     yield WaitForSeconds (1.5);
     animation.Play("Run");
 }