I still don't get it. Why is it powerfull? All i see is that it's not vulnerable to poison (one of the CC alternatives) and it gains 1 att each turn. Nothing special. Please correct me if i am wrong and tell me some uses if this card.
I think the major use is that the Death element currently doesn't have that much reliable 'CC' in its arsenal. Aflatoxin, for example, is -VERY- expensive to apply to a single creature, and if that creature doesn't die via means of healing or Rewind removal (or worse - its Malignant Cell offspring gets killed immediately after), then Aflatoxin will feel like a fairly wasted investment. Skull Shield is chance based on the opponent's creatures - Plague is also pretty expensive for its cost, and Grey Nymph has scarcely been seen in any of the PvP events/Leagues or PvE decks.
This card can technically fill in that CC option while ALSO having the capability to benefit from its own CC (a 'pseudo-Ablaze' if you will), and with that, Death won't need to worry about having to splash an alternative element (such as Darkness for Parasites) to gain the poison-effect for creature control. Then again, its stats and cost are pretty lob-sided when you play it initially, so... I don't know. ^^;