ScytherLols' Apep reminded me of this: (which I was going to post a while back).
"Stasis Keeper" / "Stasis Lord" Upgraded
Cost: 4
Stats: 2/2 - 2/4 Upgraded
Ability: Cost: 2
Stasis Link - Target Creature and Keeper are both put in Stasis until Keeper is removed from the game.
It doesn't give time another 'rewind' ability, but instead gives some more direct creature control. It is easiest to think of it as a indefinite Congeal which also effects your own creature. Whereas, an Arctic Squid can effectively shut down 3 creatures permanently, by using congeal every turn. But, this costs a lot of quanta and requires the player to remember how long a creature has been frozen for.
The stasis is obviously removed from the Keeper if the targeted creature dies or is given Immortal status. Obviously, with 6 of these in play, you can shut down 6 of your opponents creatures forever. Hopefully the cost and fragility of the Stasis Keeper will keep this balanced.
At a 6
total, and taking two turns for it to fully take effect (ie. 1st Play Creature, 2nd Use ability) should hopefully balance the fact that it is a Congeal for n turns, where n is the amount of time it takes for your opponent to apply some creature control to your Stasis Keeper.
Your thoughts on this will be more than welcome, I haven't posted a card idea in while - instead, sitting back and seeing what types of things are and are not being suggested.