Paying nine mana to untap Colossus of Sardia is just too high
Even better, it asks you to sacrifice the creatures you put counters on, which opens you up to lots of nonsense with The Ozolith
Allowing you to play lands and cast spells off the top of your deck is powerful, and getting a Treasure to help you on your way is a great addition
not every card from the Commander Deck will make it to Arena, but every legendary creature of the Commander Deck will head there, and various bundles come with Mythic Turtles, special sleeves, and more
For this Bone Dragon, it has a special ability that you can pay mana to use while the card is in your graveyard
Credit: Wizards of the Coast Citadel Gate BPhillipYork : Choose your own adventure gates, there's 5 of these, biggest thing to me is that it lets you make Maze's End decks with 3 color commanders