First, to build a sideboard, we have to have an anticipated metagame or group of decks we expect to battle against
But perhaps the most holiday-appropriate thing to do with Sky Swallower is to somehow make it appear on your opponents side of the battlefield, like the ghosts in A Christmas Carol , so your Scrooge of an opponent can share the joys of giving, too
1 Encore Electromancer (Rainbow Foil Mythic, Secret Lair Bonus 808) $1,157.82 Miku-Miku Beaming A Hole In Your Wallet This card comes singing on in, featuring the world's beloved virtual diva, Hatsune Miku
Rest in peace, Greg
That also plays into lifegain
Moving there does not qualify as a creature's demise, as the commander has already left the battlefield in some manner