The Unstable League of Dastardly Doom () is a Bablovian oligarchy, a government ruled by a small number of people. They are super villains scheming to take over the world. The league is run by a cabal, which members are constantly at odds with each other. The current roster is Baron Von Count, The Big Idea, Grusilda and Mary O'Kill.
The League of Dastardly Doom Contraptions do one of three things:
- They destroy, damage, or weaken things, including players.
- They interact with the graveyard.
- They have effects that scale with the number of creature cards in the opponent's graveyard.
These effects tend to be destructive and mean.