mtg how do battle cards work to play a card in Magic the Gathering Please help me understand combat

Design have set the groundwork for this Bonus Sheet to augment the sets value and cool factor without risking it ruining the Limited environment, and I think thats a stellar achievement worth shouting about

2/2 Illustrated by Francisco Martin Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Not Legal Comp

To prevent a card from being played once its mana is filled up, you can tap on its round icon on the top right to grey it out

You can turn an opponents single source of Red mana into a beast and lock them out of their deck for a few turns, or get rid of a pesky planeswalker with ease