The Second Doctor is a group hug creature, who removes everyone's max hand size and lets everyone draw cards, if they agree not to attack you
When you do, The Idol returns to the battlefield transformed as Sovereign's Macuahuitl, a powerful equipment card
Its trigger will almost always put a creature and a land in your hand, and it'll keep your graveyard stocked, which for some decks is almost like having an entire second hand of cards to play with
The Elemental tokens will get the bonuses, but creatures you begin to control later in the turn and noncreature permanents that become creatures later in the turn will not
Notably, March of the Machine has both serialized and Halo Foil treatments, but these are independent of one another
Practically speaking, the average creature will be out for just over three turns, which is a long time in most games