At first I thought that this was a conditional, albeit much cheaper Arrest.
Now that I think more about it, maybe the 1 cmc does outweigh the fact that your opponent can do something to negate the effect.
Why? Because of opportunity cost. If your opponent decides to pay the cost of this, while having a limited mana pool and having cards in hand, chances are you've made him choose between utilizing the creature for the turn and casting a (or several other) spell/s. Which isn't all that bad for 1 mana.
Personally, I would just run a straight-up removal. But then again, I've never played around things like this too much to attest their effectiveness (for me, same type of card as Soul Tithe; in that there's a cost if your opponent wants their creature, which can be at your advantage or "not so much")
Posted By:
Dabok
(4/25/2014 2:15:36 PM)
I think I'd rather use this than an Arrest. If your opponent has no way to deal with the arrest, they just ignore the creature outright. This one keeps them thinking" Well maybe it's worth the 
," and just twists the dagger. This is also cheap enough that I can play it later game and still easily play something else as well.
Posted By:
RedJaron
(4/25/2014 4:21:15 PM)
Good answer to turn one Elvish Mystic. What are they gonna do about it?
Posted By:
sweetgab
(4/26/2014 8:20:02 PM)
this is replacing journey to nowhere in my manabarbs deck.
Posted By:
SarpNasty
(5/4/2014 6:08:23 PM)
@Flyheight, it's almost better than Pacifism as you put a stop to the activated abilities until turn 3 as well.
Posted By:
Named_Tawny
(5/7/2014 9:01:19 PM)
what happen if you cast 2 of them on the same creature? do you need to pay the 3 mana twice to block/attack? does activated abilities cost 6 more to cast?
and do the cost increase stack with other similar card (Ghostly Prison, sphere of safety)?
Posted By:
Sorxores
(5/10/2014 10:34:06 AM)
At first, I was worried it wouldn't help me much when it was the 23rd card at the pre-release..
then, i saw targets such as mana elves, or better yet, sigiled starfish..
Seeing a guy desperately paying 3 mana a turn to scry an answer to my godsend on fabled hero.. I've never felt so evil before..
Posted By:
a7wingedsheep
(5/10/2014 8:10:05 PM)
So good. I put it in an EDH deck and I wasn't quite sure how it would perform, but putting it on Olivia Voldaren was so satisfying and so effective.
At mana to counteract the arrest, it is just enough to be too annoying to bother with most of the time. If your opponent runs out of cards to spend mana on so that they can pay for it, they're already in a really bad position anyway.
Posted By:
SAUS3
(5/22/2014 6:21:36 AM)