InvalidCastException: Cannot cast from source type to destination type.

So the following code is giving me this error. I have tried multiple .cs files and have restarted Unity quite a few times, but it keeps happening.

Tile newTile;               
newTile = (Tile)Instantiate(tile, new Vector3(j, 0, i), transform.rotation);

InvalidCastException: Cannot cast from source type to destination type. TileMaker.Start () (at Assets/Scripts/TileMaker.cs:21)

The "tile" prefab evidently isn't of type Tile; it needs to match the variable you're assigning it to. (Restarting Unity won't make logic errors go away.)