As a fine card on its own and one that's incredibly strong with other Humans on the battlefield, this is a great example of what you're looking to play in these kinds of decks
The reverse of Battle cards will often feature a powerful effect that the winner of the Battle gets to use, making them viable and unique targets for attacking during your games of Magic: The Gathering
At instant speed you can pay to make X 1/1 Citizen dorks and your stuff gets indestructible for the turn, which is a nice variant on your answers to mass removal, and this is a strong combat trick where you can cast this after an attack your way, make a bunch of 1/1s, block, and keep them alive, or you can just use this in response to a big sweeper like a foe's Wrath of God when you only have two for the X to save your team and get in a Commander bump
Unfortunately, in practice, its impossible to find a commander thats perfectly equipped to leverage all aspects of a singleton-buster, so lets dissect Slime Against Humanity into its constituent parts