[IBM] Any one of the fat cables that lurk under the floor in a dinosaur pen.
Possibly so called because they display a ferocious life of their own when you try to lay them straight and flat after they have been coiled for some time.
It is rumored within IBM that channel cables for the 370 are limited to 200 feet because beyond that length the boas get dangerous --- and it is worth noting that one of the major cable makers uses the trademark "Anaconda".