While it doesnt untap on its own, support from cards like Voltaic Key or Unwinding Clock keeps it running smoothly
Wattson, Flannery, and Winona tried to stop it but failed due to Team Aqua's interference, and it ended up reaching Sootopolis City, where it fought for days on end with Groudon
Not only does it improve your draws, it also ramps you and draws you a card when you need it for just a Treasure token
Plus, it gets a defensive Your Turn effect while you have 0 or less memory
As such, in grind games when your opponent's graveyard is empty, you can use cards in your own graveyard to take advantage of Deathrite Shaman's effects
You can only use each effect of "Metaphys Ragnarok" once per turn