mtg battle cards rules What is a Card in Magic: The Gathering? Battle - MTG Wiki

The combo works by having Kumena or Drowner of Secrets tap some of a Merfolk to activate any of their abilities, which will then cause the Pilgrimage to trigger, generating us a merfolk token, which in turn triggers our Alarm, causing all creatures to untap

However, the true power of this card comes in the form of its ability that triggers when it enters the battlefield

Tinker doesnt even need a second card to be absurd, although frequently it was combined with Time Walk to great effect since all you need to do is untap

Teferi, Hero of Dominaria will always be a force in competitive play, even seeing some action in Azorius Miracles in Legacy