The Science Behind The X-Files:

El Mundo Gira

• The strange forces at work in this episode play upon the Mexican migrant workers' fears of a mythical beast called El Chupacabra. Literally meaning "goat sucker," the Chupacabra myth originated in Puerto Rico, and the creature is blamed for many goat and livestock mutilations around the world.
  
  Chupacabra page: http://www.princeton.edu/~accion/chupa.html
  I know this isn't science yet, but that's what I'm leading up to...

• However, Agents Scully and Mulder have a more logical explanation for the strange deaths in the case of "El Chupacabra." When scully goes to perform an autopsy on the first victim, a young woman whose eyes and mouth had reportedly been eaten away, she finds the body overgrown with Aspergillus fungus. This fungus usually only preys on humans with immunodeficiency problems.
  
  For more information, go to http://www.iapac.org/clinmgt/diseases/fungal/asper.html, which medically explains the ramifications of an Aspergillus infection. The study of fungi is called mycology, and the University of Texas Medical Branch has an entire site devoted to fungi at http://fungus.utmb.edu/.

• Scully takes a sample of the overgrown fungus from a second victim (the bus driver of an INS vehicle) to the local university for some testing. What she finds is that the man they are looking for has been infected with some kind of enzyme that accelerates fungus growth.
  
  INS web site: http://www.ins.usdoj.gov/
  For more information on enzymes and how they work, check out http://www.novo.dk/backgrou/backgrou/baenzuk.htm, a page from Novo Nordisk, a company that genetically engineers industrial enzymes.

• Of course, Mulder has his own hypothesis concerning the enzyme's origins. He thinks that the enzyme is extraterrestrial, coming from a bolide, a supersonic extraterrestrial object that hit a lake near the migrant camp, tainted the water with the enzyme, and (from the force of the impact) blew it all into the air, causing the strange yellow rain that the workers in the camp described.
  
  To read about bolides and find out what they are, look at http://woodshole.er.usgs.gov/epubs/bolide/introduction.html, a page from the US Geological Survey.