I used the Spikes.png that Rick supplied us and created a couple of hidden spikes hazard.
I gimped a bunch of sprites using the sprite supplied. Then added game objects with a renderer, collider, rigidbody, and animator using my gimped sprites. I added Hidden Spikes layers, but the Hazard layer could also be used. The collider is turned off while the spikes are not visible.
If you use the hazards layers, nothing needs to be added to your Die() method in the player.cs. If you add Hidden Spikes layers, you need to add them to the player.cs.
Both hidden spikes prefabs and sprite zip files for making animations can be downloaded HERE.
For now, my work can ONLY be used in the course project.
Update:
I was told by Rick, that I can do what I wish the spikes hazards I created using his spikes.png asset. Therefore, those wishing to download MY hidden spikes hazards can also do what they like with them.