It's more like extended borrowing." Number 67 Language English Legal Formats Commander, Legacy, Modern, Vintage Not Legal Formats Alchemy, Brawl, Competitive Brawl, Historic, Pauper, Pioneer, Standard, Timeless Rulings (10/4/2004) If there is no legal place to move the enchantment, then it doesn't move but you still control it
You need to have already declared an attack with it, so it has 10,000 Attack Power
That said, the card doesnt technically draw cards (neither does Bolass Citadel, but that card doesnt really need support to work)
Now, to be fair, my list is being considered from a kitchen table viewpoint
Similarly to Planechase, this is an optional format that needs to be agreed upon by players prior to starting a game
If youve got a board developed enough for the Overrun effect to finish an opponent, youve likely got sufficient board presence to keep Garruk defended