Dumblocks

The Dumblocks are a humanoid species of stupid, vicious brutes who live underground. They are one of the two species the human evolution will be diverged into by the year 5000000. The Dumblocks will live side-by-side with the intellectually and morally advanced creatures until 5000005, when they will rebel and take over Earth.

Trivia

 * The Dumblocks resemble the from the  of ' early science fiction novella , and are presumably named for them.