They are calling this the rarity key, and the rare, super rare and legendary symbols will be holographic on the cards (or some kind of shiny gradient), to make it even easier to differentiate
cards because it delivers raw power with built-in protection, making it one of the hardest classic monsters to answer cleanly
These cards are often found in Azorius (white and blue), and Esper (white, blue, and black) libraries as part of the infamous Stax deck, which aims to slow the game to a crawl, and winning by making everyone lose
You may play it until you exile another card with Unstable Amulet
If you spend instead, you get two 1/1 kithkin tokens for extra bodies, and the evoke option lets you grab the enters trigger cheaply even if the creature doesnt stick around