Scotus' tapeworm

Dr Scotus had an alien tapeworm which lived within him and controlled his thoughts.

Believing that nobody would buy weight-loss pills from a fat nutritionist, Scotus tried one of the pills himself - in actuality an alien tapeworm egg. The parasite gave him cravings to eat anything at everything, cravings which Scotus suppressed using protein supplements, drugs and sedatives.

Eventually, the creature reached a stable weight. The tendrils of the parasite, however, continued to grow, permeating Scotus' brain and nervous system and reaching out through both his scalp and groin; they appeared to be blonde hairs, but on closer inspection waved independently in the absence of any breeze.

The parasite wouldn't allow itself to be harmed, so Owen Harper dissolved one of Scotus' herbal tablets in a solution and injected it into him. The parasite died, and, with the creature so deeply embedded within him, Scotus died with it. (PROSE: Slow Decay)