Mangala in Karkata rashi is like an active little boy who wants to climb trees and play "war"; but His over-protective mother (Chandra) keeps Him inside the house, where He gets more and more unhappy and restless. Eventually he becomes disruptive and even abusive. He cannot find a socially approved way to channel his physical energy within the constraints of his mother's house.
Mangala a troublemaker when He is plunged into unsuitable environments and no environment is more hostile to Kuja's direct, assertive, competitive character than Karkata.
Mangala is called "neechcha" (fallen, debilitated) in Karkata rashi because the sign of the Moon is an exclusively emotional, protective, embracing, and parental place. Karkata is the realm of the protective mother, the childhood home, the mother's native culture, one's cultural roots. Karkata is patriotic, defensive, and a guardian of the homeland.
Imagine a crab creating its home from beach debris and then defending its home as best it can. When threatened, the crab walks sideways in a distracting motion; the crab never lunges forward in attack. Yet the crab is determined to protect its home. The crab represents Karkata: need for a home, withdrawal into the safety and protection of home, nurturing and care within the home.
