It's a thing, but could also be an idea.
Twinax, short for twinaxial, is a network hardware invented by IBM to punish us.
It's a two-wire system with big fat cables, and requires each device have a specific, location dependant address. Needless to say, it is not fun and decidedly a Bad Thing.
Oh, yeah, and to top it all off, it runs SNA -- Metophoricly like decapitating someone after you've defenistrated them.