FusionDex

In order to take up more water, Sunbro transformed its tail into roots to reach deeper into the ground. If you need to move it, you can safely detach its tail; it can grow a new one. The detached tail may psychically mutate into its own plant.

Its tail has a Shellder firmly attached with a bite. Sunbro try to minimize movement to conserve the nutrients they have stored in their bodies for evolution.