parasmitic
Describing behavior that is both parasitic and smitten (a portmanteau of both words); often answered with unexpressed revulsion by the object of the leeching affection, thus enabling subsequent parasmitic behavior. Expressed revulsion will frequently dislodge the parasite, thus leaving only unrequited affection.
Her overseas Facebook stalker was merely annoying until he booked a flight to her home town and announced his arrival, assuming he should stay at her place. She decided the racking sound of a 12 gague would dampen his parasmitic ambitions. Nonetheless, he continued to make phallic banana jokes.