I really like the theme of this card, but it's too strong. I would recommend one of the following changes:
-Damage reduction of 1 instead of 3, so as not to outclass diamond shield, or more importantly, the in-element permafrost shield, since that's more of a direct comparison, both being water cards
-Remove the damage reduction totally and give it a fog/dusk-like effect where it blocks, say, 33% of attacks, and on each blocked attack, the dragon might get released. (either the current 20% chance per absorbed hit, or else it is released automatically after, say, 6 successful blocks or whatever number)
Also, do you intend for an ice/arctic dragon to be released every time, or a random dragon? I think random dragons would be cooler, but possibly less thematic. Maybe something like 50% water dragon 50% one of the other 11 at random, and 50% chance to start frozen.
