parasitic

Of or pertaining to a biological or symbolic parasite.

Drawing upon another organism for sustenance.

Exploiting another for personal gain.

Intellectually, logically, conceptually, or metaphysically dependent (on something else in the same category)

Of emotional damages: accompanying a physical or pecuniary injury.

A component of a circuit that does not show up in a circuit's schematic but does show up in the circuit's behavior.