: Sounds like something out of a Douglas Adams book (hitch
: hikers guide to the galaxy)
Nope. The word isn't actually defined in the show (there's another hint), other than being the name of snake-shaped ray guns that hurt a whole damn lot. It's never actually spelled either, but the later Egyption phonetic scripts had no vowels ("Ra", the sun god, was something like the modern Rx sign, except it was supposed to be an eye with a teardrop in one corner). Thus, 'zadnikutel' would be 'zdnktl'.
Another hint; only one hit hurts a whole damn lot. Two will kill, and a third with vaporize the target.