A person who cannot or will not take care of themselves, often due to addiction or derangement, and who in desperation pulls anyone who tries to help them down alongside them, the way a drowning person pulls their would-be rescuer under the water.

Adj. Something that is expected to have a long lifespan by virtue of having existed for a long time, based on the lindy effect, named for the New York restaurant Lindy's, coined by Albert Goldman and popularized by Nassim Taleb.