Man, this card was really good in its day. Making a creature unblockable? Before this, the best way to do it was with Invisibility and that's not the greatest. It allows for some creatures to block it and telegraphs the fact that that creature will be pumped for extra damage. This card was really good in its good. The operative word being "was". Why do I say "was"? Ehem, Aqueous Form, Artful Dodge, Distortion Strike, Infiltrate, and Veil of Secrecy. Need I say more?
Pros: Makes a creature unblockable
Cons: Costs way too much, timing restriction
Note: I just want to say how much I hate the change of "unblockable" to "can't be blocked". It's longer word-wise and clunkier to say. I think it's dumb and will not be using the terminology "can't be blocked" here. It will always be "unblockable" in my mind!