Stated by Chazz to be Crowler's "trump card", after the latter Summoned it, in Yu-Gi-Oh
Of course, this last part also benefits the creatures controller, but thats the beauty of this cardit can save your creature from dying in combat while also letting you draw cards
[5] Set: D23 Promos Rarity: Promo Let It Go is a Song card that was only given to the top 64 or 128 participants in regional tournaments
Note: For fusion monsters only
I can imagine a third card where Teferi tells Urza, "It is today." Teferi may have screwed up Urza's plans but he saved his own people from an apocalypse that ruined everything else by tucking them away temporally, so I'm on Teferi's side on this one
Youd happily pay the extra mana to tack on all of Stoneforge Mystics benefits: this Kor artificer is a body on board, and an activated ability that can cheat equipment into play