Basic Trope: A character uses a machine that reverts other characters to an earlier or previous state of evolution.
- Straight: Emperor Evulz' evil plan is to use a device he built to turn all of humanity into Australopithecus anamensis, making them too stupid to stop him from robbing several banks.
- Exaggerated: Evulz uses the device to revert every organism on Earth into single-celled form so he can rule over them.
- Downplayed: Bob, a Teen Genius, uses a simple device to temporarily turn every student in his school into Homo erectus humans, ensuring he'll become valedictorian of his class by virtue of being the smartest by comparison.
- Subverted: Emperor Evulz' devolution machine appears to work, turning humans into prehistoric apes...until it's used on a cat, and the cat also turns into a prehistoric ape.
- Double Subverted: The machine does work, and that cat was a transformed human from the Emperor's previous endeavors.
- Averted: No machine that reverts characters to previous evolutionary states exists.
- Played for Horror: The machine is used on various people's dogs, turning them into wolves. Feeling threatened by the humans in close proximity to them, the wolves attack.
