The Spikes_Down animation looks like it's the exact reverse of Spikes_Up, just slower. I was able to make the transition from Spikes_Up directly back to Spikes_Idle using a Duration Time of 1.5. So is Spikes_Down even needed in this example?
Also wondering, why did the spikes go through the ball at 03:42? Did the Rigidbody just fall asleep? Would we have to call WakeUp() on the ball in the Update() method?
The spikes down animation is really not needed but it was included with the model so I used it. You can also have it setup with just one animation since it will technically reverse itself due to how the animations play.
As far as the spikes going through the sphere I'm not quite sure if the rigidbody fell asleep or if the collider on the spikes didn't follow the spike mesh when going up.