Ab-SENT-i-theen n.
Absentithine is an old Hollywood term, also found in general science fiction media, used as a temporarily "working" name for any fictitious element or compound which has importance as a plot device. Better known examples of
absentithines include the original script of "The Absent-Minded Professor," in which
absentithine was eventually replaced by the word "flubber" during pre-production, "adamantium" and "vibranium," both used in Marvel comics and movies (examples of which include Wolverine's claws and Captain America's shield, respectively), and "Chemical X," which, along with sugar and spice, created the Powerpuff Girls.
The mad scientist intended to preserve the bodies in an
absentithine solution, but instead, unwittingly unleashed the zombie apocalypse.