Cavalier of Dawn [Core Set 2020 Prerelease Promos] Continuous Trap you can Tribute 1 monster

you can Tribute 1 monster to have this card gains ATK equal to the original ATK of the Tributed monster until the End Phase of this turn

(You still pay its costs

Set: Avacyn Restored Type: Creature — Beast Rarity: Mythic Cost: {5}{G}{G}{G} Haste

This explains why the goblins remain unaffected

you cannot Special Summon monsters

Cavalier of Dawn [Core Set 2020 Prerelease Promos] Continuous Trap you can Tribute 1 monsterSet: Core Set 2020 Prerelease Promos Type: Creature Elemental Knight Rarity: Mythic Cost: {2}{W}{W}{W} Vigilance When Cavalier of Dawn enters the battlefield, destroy up to one target nonland permanent. Its controller creates a 3 3 colorless Golem artifact creature token. When Cavalier of Dawn dies, return target artifact or enchantment card from your graveyard to your hand.