Starting Valentine's Day at Walmart you can find select General Mills cereal boxes with Skystones! They will reportedly release to other retailers in March. The specially marked boxes contained a sealed box, in a sealed bag, in the sealed cereal bag. The inside front of the box has 2 Skylander Coupons you can print out. The back of the box has a Skystone board you can cut out.
There are 4 Unique Sets to collect. I presume each set will have a different character on the box. The set I got has Krpyt King on the box. Inside the box you have 10 Skystones. 2 0f the 10 are special "boss" Skystones that have a glittery/holographic look in addition to much more impressive Skystone utility. You also get a Skystone shaped instruction sheet and a coin to flip that has a Blue and Red side. Each Skystone has a front and back and allows you to play against a friend as you each get 5 cards.
I am including some pictures down below, including the Skystones included in this box. If you get the same box, be sure to compare Skystones and see if they are the same. Similarly, if you land a box with a different character on the front, let's document the available characters and Skystones to help everyone out.
Cinnamon Toast Crunch Skystone Box
Front
Back
Krypt King Box: Includes Dr. Krankcase and Chompy Mage Boss Stones (Blue)
Krypt King Box: Includes Dr. Krankcase and Chompy Mage Boss Stones (Red)
