That being said, I'm not sure if it's worth fizzling all of your own spells to make mass tokens, I'm sure it's fun to try though
Magic: The Gathering Doctor Who is our way of bringing the world of Time Lords and Daleks to Magic
Cards that force players to have enough basic lands to make do in an emergency such as Blood Moon are one thing, but cards that will outright kill you are another
Assuming you do a little bit of setup (easily achieved with access to greens ramp and blacks tutors), you can have some protection spells ready with Swiftfoot Boots, some Impact Tremors-like effects, and some sacrifice synergies like Blood Artist and Mayhem Devil to maximize the damage those Kobolds deal on the way in and on the way out
-sigh- Commanders emphasis on color identity in deckbuilding has successfully kept Krrik, Son of Yawgmoth from being a huge problem in the format as a whole, but its still a powerhouse that should be removed or countered on sight against decks with a large or exclusive emphasis on black, as 4 mana can easily become as much as 16, more if life gain enters the equation