After being curious about what happens when someone cloaks a stun block, my friend and I did a bit of testing. The testing yielded some curious results.
It appears that once you cloak a stun block, the card is turned into a single shield with a "?" on it. The kicker is that by doing this, the stun block no longer performs its function. Instead, if a stun is cast upon you, you will be stunned as normal and receive the corresponding stun blocks depending on the size of the match.
That never happened with me. It work perfectly. And the on the shield is so that the other player cant see what the shield is and doesnt know how to trigger it. Also a sun icon appears while waving your wand around so they cant figure out what shields thaty are and work around them. It is mainly best for pvp, but also great for showing off to friends that you can now use an astral spell. XD i do that all the time! 8)