time vampire

noun2

1. •
   (informal) A person, obligation, or activity that drains one's time; a time-waster.

   • The telephone is to time vampires what blood banks are to real vampires. — 1994
2. •
   A variety of vampire that feeds off time or potential years of life.

   • Do you mean that Jarmyn Thanatos is some kind of a— a time vampire? — 1997