Chemical X is a Shop Relic that makes cost X cards act as though the player spent 2 more energy on the card then they actually did. For example, playing Whirlwind with 3 energy normally causes 5 damage 3 times, but with Chemical X, it would cause 5 damage 5 times. Chemical X also allows cost X cards to be played with 0 energy and still have an effect of 2.
The reference is made evident by the flavor text, as the Powerpuff Girls were created by the combination of Chemical X and "sugar, spice, and everything nice".
