I think this will be another addition to the category of hax shields.
So far I don't see anything wrong with it. If the cost will be increased I hope it'll be just 3|2 similar to solar shield.
There might be a visual bug when you have a skull buckler and your opponent's creature dies due to other reason. For a split second, it will show a blank creature with 0 cost skill and then disappear. Couldn't get a screen shot; it's too fast.