one piece tcg luffy deck Green Purple Profile & Guide reveal up to 1 Supernovas type card other than [Monkey.D.Luffy] and add it to your hand Black/Yellow Luffy - Deck Overview

So, while it can win a game, it isn't as guaranteed as the rules text makes it seem

Mercurial Chemister is particularly awesome because, even though most of the time it will be used to draw cards, the discard effect could prove useful as removal too

There is no mention of a minimum or maximum mana cost for the creature , meaning you could theoretically bring any creature to the battlefield for free

Fang and Vanille have such a strong relationship in FINAL FANTASY XIII that we knew their cards had to relate to each other in some big way

One of the more common situations is your mana rock doubling up as a combat participant