Is this a kind of CC or a buff to your creature?
Despite what blarp is saying, this card is intended to be used as either a last ditch effort pull out more attack damage or to drop your opponent's.
For the way it is right now, the card gives opportunity for both CC and buff. Because I have yet to give percentages to whether there is a drop or increase for either attack and or max HP, this card does not stand out as either a better CC or a better buff.
Entropy is about this ideal that we may not know the exact outcome of something, and it could either be good or bad, but no matter what happens, it's luck. (or plain old RNG)
Take for example Disco or Pandies. You don't know exactly what will be happening when you use them, but you use them anyways in hope of a good outcome for you and your duel.