Its not unreasonable to think you might just draw twenty cards, right there, and if your deck contains a very unusual amount of mana, you might not be far from drawing your whole deck (especially if youve got a couple of Dakmor Salvages somewhere in the mix, making it completely deterministic that you mill your deck, fill the battlefield, and set up some graveyard kill)
The Night Stretcher UR 137/106 stands out as one of the key utility cards in the Super Electric Breaker set
Promos Promos are cards that are either included in a Pokmon product (such as an Elite Trainer Box) or given away during a promotional or special event (such as a Pokmon TCG tournament)
The issue, then, is not as much justifying playing Boseiju in those decks, but rather featuring it in a Cube at all
Take a gander at the decklists, and then we'll jump into the rankings