Blob Shadow

using UnityEngine;
using System.Collections;

public class BlobShadowScript : MonoBehaviour {

    [Header("Settings")]
    public Transform blobShadowParent; // Parent GameObject with child (child is square mesh with shadow texture)
    public Vector3 blobShadowParentOffset = new Vector3(0f, 0.01f, 0f);
    public LayerMask layerMask;

    void Update()
    {
        Ray ray = new Ray(transform.position, -Vector3.up);
        RaycastHit hitInfo;

        if (Physics.Raycast(ray, out hitInfo, 100f, layerMask))
        {
            blobShadowParent.position = hitInfo.point + blobShadowParentOffset;
            blobShadowParent.up = hitInfo.normal;
        }
        else
        {
            blobShadowParent.position = hitInfo.point + new Vector3(0f, 1000f, 0f);
        }
    }
}