Combos nicely with Mystic Snake
Even if you never use it, you threaten to punish those that tap out during their turn. That is kind of like a four mana card that destroys a land of each of your opponents.
Capitalize on that with Avalanche Riders, Invader Parasite or Acidic Slime. Which, incidentally, combo with the portal...
Posted By:
kiseki
(2/15/2012 12:04:05 PM)
very useful card. you can use to return opponent's creatures when he has no mana to pay.
Also, the best way to use it, you can use it to return your own creatures, specially "when it comes into play" ones. very nice card.
Posted By:
Guest1334148255
(9/19/2009 8:08:59 AM)
@MojoVince: I think you may be misunderstanding the rules of the verb "exchange". An exchange can only take place if both permanents are on the battlefield at the time the ability would resolve. So if you are suggesting to play the drake, bounce it in response to it's trigger, then get your opponent's creature without giving him anything, that won't work. If you're saying bounce the drake once your opponent gets it, that would work but would require your opponent to not have any mana available.
@John-Bender: Equilibrium's ability costs 
plus the cost of the creature and can only be used (most of the time) when you can cast a sorcery. Erratic Portal can be used any time, can save your own guys, and forces your opponent to keep mana up. Equilibrium is good, but so is this card.
Posted By:
ForestFire0
(6/26/2011 8:30:22 AM)
my favourite card of all time, the combinations are endless and since it's an artifact it's effective for any color of deck.
Posted By:
ajcanuck
(4/29/2010 4:07:58 PM)
Priest of Gix or Ball Lightning maybe?
Posted By:
Arthindole
(1/18/2011 4:08:36 PM)
And with this :
Gilded Drake
Take an opponent 's creature per turn for 3 .
Posted By:
MojoVince
(3/21/2010 11:36:07 AM)
Erotic Porno
Posted By:
ibasawder
(7/31/2012 12:18:55 PM)
Great for saving your own creatures, can get problem creatures your opponents control out of the way. Blue has better options, so put this in non-blue decks. Say, a black deck with new 2011 creature Phylactery Lich or some other big black creature that has a drawback that can hurt you if you can't get rid of it at the right time.
Posted By:
A3Kitsune
(6/29/2010 10:01:16 PM)
I don't understand what WotC where thinking. Why was this in the same pre-con as Equilibrium? Equilibrium has a better bounce ability and the only cost is . I just don't get it :S
Posted By:
John-Bender
(12/21/2009 4:44:07 AM)