You can build a deck, but you won't be able to save it
It really helps that Gladion makes Silvally decks even more consistent, able to put Type: Null or Silvally directly into your hand
Starting with Khans block, this was the new normal, as their holiday break once starting as late as Saturday, December 22, was now starting as early as Saturday, December 12, and a December return to the office was a given
Normally, players would get a chance to respond before the ability resolves, but Doubling Cube's ability is a mana ability, so 605.3b says An activated mana ability doesnt go on the stack, so it cant be targeted, countered, or otherwise responded to
1: These cards arent playable in your main deck, usually because theyre too situational, but they could be useful out of the sideboard or might be the last card you add
Might as well play them