Official Magic cards printed by Wizards of the Coast are legal in sanctioned play, so long as they dont have a special size or thickness
Illustrated by Joshua Raphael Standard Legal Alchemy Not Legal Pioneer Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
Giving all your slivers indestructible greatly limits your opponents chances of responding
Instead of being named Void Beckoner its called Spacegodzilla, Void Invader. But you might notice that the original cards name is still there under the new name, as well as all of its original text and abilities
That said, if you look at this one as a two-time recursion piece for Enchantress or Artifacts decks (or even Superfriends decks) that leaves behind a creature to wield said permanents (or protect them), then this becomes a more interesting card
Doom Whisperer speeds up graveyard setup, and Children of Korlis unlocks explosive turns