Zirda, the Dawnwaker (233) [Ikoria: Lair of Behemoths Promos]

Companion — Each permanent card in your starting deck has an activated ability. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.) Abilities you activate that aren't mana abilities cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana. {1}, {T}: Target creature can't block this turn.