As far as floors go, thats not a bad place to be
This is a powerful Yawgmoth's Will, one of the most powerful cards ever printed and so powerful and nasty that it's restricted in Vintage and banned in most other formats (but not Commander, oddly enough)
The new reprints of it feature both a standard and a full-art version, with the art on both being more abstract than some of the previous installations
rather, it keeps its lair full of servants and dispensable thralls
And even though you are guaranteed one in every collector booster, with 45 to choose from, the chance of opening a specific mythic is going to be pretty low
Not only is that a phenomenal effect, but it is on an instant spell as well