As long as its on the stack, players cant cast spells or activate abilities that arent mana abilities, which means Stonewood Invocation isnt getting countered either
Since Urborg, Tomb of Yawgmoth makes all lands into Swamps, so long as someone at the table has a copy in play, you can recur Bubbling Muck and untap lands as often as your cards will allow before casting a spell like Exsanguinate or Torment of Hailfire to win
I'm not really a card game player myself, but playing the GB version has renewed my interest in the actual TCG
Commander is also fond of two other types of mulligans in casual games
Zamazenta 97/159 - Crown Zenith Holofoil Zamazenta 97/159 - Crown Zenith Holofoil The Pokmon Company If this Pokmon has any Energy attached, it takes 30 less damage from attacks (after applying Weakness and Resistance)
You care about huge global popularity and long-term collectability