Some have a temporary effect, but most continually grant the effect while theyre on board or until the end of the game
There are also 22 in the Collectors' Edition, 9 in the International Edition, 9 in the Alpha Edition, 20 in the Beta Edition, and 1 graded Press Check Edition
Mana Drain is exceptionally strong, and most other Magic counterspells cost far more and do far less
Deck building on a phone works, but it's slower and more awkward than a browser-based editor with a full keyboard and screen
Instead characteristics of the box (such as there being a green-winged Charizard on the side), and very carefully being able to identify the packs within (without impacting the seal) is the way of identifying whether a box is shadowless or not
Each player may respond to this triggered ability as normal