The facts of nature are what they are, but we can only view them through the spectacles of our mind. Our mind works largely by metaphor and compariso… - Stephen Jay Gould

In short, the root-head turns the crab into a Darwinian cipher, a feeding machine working entirely in the parasite's service. The castrated crab can make no contribution to its own evolutionary history; its "Darwinian fitness" has become flat zero. ...But ever so carefully, for the parasite must maintain the crab in constant and perfect servitude - not draining the host enough to kill this golden goose, but not letting the crab do anything for its own Darwinian benefit.

Lernaeodiscus porcellanae turns control of the host into a fine art. After castration by the parasite, male crabs develop female characteristics in both anatomy and behavior, while females become even more feminized. The emerging externa then takes the same form and position as the crab's own egg mass... The crabs then treat the externa as their own brood. In other words, the parasite usurps all the complex care normally invested in the crab's own progeny.

[A]s we discern a fine line between crank and genius, so also (and unfortunately) we must acknowledge an equally graded trajectory from crank to demagogue. When people learn no tools of judgment and merely follow their hopes, the seeds of political manipulation are sown.