There are a few white cards informally referred to as “Flicker” cards that exile a permanent and then return it to the battlefield, either immediately very soon after (such as at the beginning of the next end step). White has a lot of these effects, frequently specifying that they can only hit things you control- which lets you dodge out of the way of a kill spell, or re-trigger an enter the battlefield effect. All good. But it is very important to read the effect carefully.
There’s three basic ways flickering can be worded. The first is things like Justiciar’s Portal– “exile something, then return that card to the battlefield under its owner’s control”. If you’re trying to steal something permanently with Act of Treason, this won’t help at all; it’ll just give them the creature right back! But let’s say your opponent stole a creature of yours with an Entrancing Melody. You can snatch it back with Act of Treason for a turn, but they’ll just get it back again… unless you flicker it! Hit it with Justiciar’s Portal and it’ll come back under its owner’s control- and that’s you. It’s a new object to the game, so your opponent’s control-changing effect is gone, and your creature is yours again.
The second way flickers can work is “exile something you control, then return that card to the battlefield under your control”. There’s no examples of this in standard at the moment, but things like Restoration Angel and Cloudshift have used this wording in the past. In this case, the only condition is that you’re the current controller, and when it comes back, you become the new default controller. You’ve stolen it for good! Great work!
Enter Lumbering Battlement. Lumbering Battlement has the third kind of wording: “exile any number of other nontoken creatures you control until it leaves the battlefield”. It’s a lot like Banishing Light, in that the cards are gone until a specific condition is met, rather than for a set length of time. But where exactly do the cards go when Battlement pops? It doesn’t specify at all, so how do you figure this out? Unfortunately, when a “one-shot effect” like this doesn’t specify otherwise, the cards will return under their owner’s control, so you won’t be using Battlement to snatch any creatures long-term. You’d best keep them locked up in the battlement as long as possible!Today’s Rules Tip was written by Alistair Crook