Lab Notes
If Looks Could Petrify

In my professional opinion as a science-fiction writer, part of the secret to Chinese food is basil. A sweet, pungent herb native to Asia, it imparts a distinctively yummy flavor to meat sauces. It's sometimes known as the "king of herbs" because its European name comes from the Greek "basileus," meaning "king."

On the other side of the Pacific, several species of American tropical lizards go by the name of "basilisk," not because they're fond of basil but because a crest on their heads and backs creates a superficial resemblance to a mythical creature of the same name. Also known as "Jesus Christ lizards," these small reptiles are capable of running upright along the surface of a still body of water, supported by high speed, low weight, webbed feet and surface tension.

However, they couldn't easily be mistaken for a "real" basilisk, as the new SCI FI original movie Basilisk: The Serpent King makes clear. In fact, the name "basilisk" comes from the Greek "basiliskos" or "little king," because the mythical animal supposedly had a crest or comb structure on its head that resembled a crown. Ironically, though, the mythological creature wasn't all that little, being anywhere from the size of a turkey to a good-sized crocodile. It was also vicious and very, very poisonous.

The basilisk of classical legends was venomous not only by bite but by contact, with the poison being so powerful that it could even travel up along a spear or pole used to kill the animal, so that the hunter would die as well. As if that weren't enough, medieval writers insisted the creature could also exhale a toxic vapor from its mouth, or kill with sound waves by producing an unbearable hissing noise, or even kill—literally—with a glance. This sounds fanciful enough that I'm not sure anyone actually believed it, but a less elaborate version of the basilisk was described matter-of-factly by Greek and Roman writers, who seemed to have little reason to doubt the animal's existence.

Here's venom in your eye

The Roman historian Pliny the Elder also described it as traveling upright rather than slithering along the ground. Even earlier accounts come to us from Egypt and Israel; the Old Testament calls the creature by the Hebrew "tzeph'a" (translated as "basilisk" or "cockatrice") and refers to it as a "fiery flying serpent" and a venomous, biting creature whose eggs are toxic if eaten. Among the sillier legends, the basilisk would supposedly die if it heard a cock crow, or if it saw its own reflection. For this reason, people hunting the basilisk are sometimes described as using mirrors for both offense and defense, just as Perseus did when hunting Medusa.

All this may be a garbled description of the hooded cobra, native to Africa, South Asia and Australia, which really does rear up to intimidate its enemies and can slither forward in this position, with its head well raised. One particular group of species—the spitting cobras, found today only in sub-Saharan Africa and parts of Asia—seem like an especially good fit, since they can accurately direct a stream of venom at targets up to three meters away, aiming preferentially for the victim's eyes. With the details of an encounter handed down from person to person and generation to generation in a giant game of "telephone," it isn't hard to imagine this description slowly morphing, until "spitting poison at the eyes" turned into toxic vapors and gaze weapons.

Interestingly, the weasel is often cited as being immune to, and a natural enemy of, the basilisk. This is probably a reference to the mongoose Herpestes, which uses superior reflexes to attack venomous snakes and is sometimes kept in homes for this reason, as in Rudyard Kipling's classic tale "Rikki-Tikki-Tavi." The legends about the crow of a rooster may relate in some way to the fact that cobras can be hypnotized by music and are therefore a favorite of snake charmers. (The charmability of the basilisk is even alluded to in the Old Testament, albeit tangentially.) The king cobra can grow up to 18 feet (5.6 meters) long—a monster indeed, and worthy of legend!—although spitting cobras are less impressive, usually under a meter in size. As for toxicity, most cobra venom is actually fatal in humans only about 10 percent of the time, although fatality rates are much higher for certain species, such as the (non-spitting) African cape cobra. Even where the poison isn't fatal, though, it can cause blindness, paralysis, anemia and other unpleasantness.

The basilisk's most interesting ability—petrification, i.e., turning its victims to stone simply by looking at them—plays an important part in modern fantasy stories and in role-playing games like Dungeons & Dragons, but it actually seems to be a late addition to the legend. The oldest reference I could find comes from Vienna in the year 1212, where a basilisk supposedly turned children to stone and then, when shown its own reflection, was turned to stone itself. Allegedly the well still exists today, and the legend is happily retold to explain the curious statuary surrounding it.

Is this possible? If an animal really had an ability like this, how would it work?

Nothing is certain save death and toxins

The most obvious (and least science-fictional) version would be a toxin that simply induces muscle contraction and death, followed by rapid onset of extreme rigor mortis (i.e., stiffening of the corpse), creating "petrified" victims frozen in various positions of horror. A number of toxins fit this description, although strychnine and certain herbicides such as bentazon are particularly known for it. Which is interesting, since the touch or breath of a basilisk was thought to kill plants as well as humans and animals. Indeed, the area around a basilisk den was often described as dry, lifeless and devoid of vegetation.

Another possibility is some sort of secreted resin. Under the right conditions tree sap turns into amber, which looks and feels like a type of stone even though it contains no silicate minerals. In the animal kingdom, bees produce wax and honey, worms and spiders produce sticky silk, whales produce ambergris and almost all animals produce copious quantities of mucus. It isn't far-fetched to imagine a spitting reptile whose secretions harden on contact with air, forming a sort of organic cement that might look a lot like stone, especially if dirt and pebbles mixed with it while it was hardening. The illusion would be even more convincing if this substance also included contact poisons with the characteristics mentioned above. Could the basilisk legends simply reflect a species of spitting reptile, now extinct, whose venom included herbicides and organic resins in addition to the usual neuro- and hemotoxins? Probably not, but it's an interesting idea.

But hey, this is science fiction, right? What we really want to know—what geeks everywhere are dying to know!—is what it would take for a creature to turn its victims into actual stone. Happily, the answer is simple: nuclear fusion. In the interiors of massive stars, tremendous heat and pressure squeezes carbon and oxygen atoms together to form sodium, magnesium, sulfur and silicon. If this happened inside the body of a living creature—if even a tiny fraction of the organic molecules were converted to silicate minerals—the chemical composition of the flesh would be transformed dramatically. In addition, the process would release a lot of heat—nearly 10 billion joules per gram, or enough to boil three and a half cubic meters of water. If this happened in an instant the body would simply explode, but a slower, more agonizing process would drive water out of the body and char the remaining organic molecules, leaving behind a scorched, partially fossilized corpse that really might resemble a statue carved from rock.

Yes, gentle reader, I hear your objections. Nuclear reactions don't occur in the animal kingdom, right? Well, an organism from an alien ecology might somehow evolve the capability to shoot particle beams from its eyes (muon-catalyzed fusion, anyone?), but a much easier mechanism involves sound waves. Remember, the basilisk can kill with a hiss, and in fact, a phenomenon called sonoluminescence (see "Cold Fusion Heats Up on the Net," March 2000) uses sound waves to produce tiny bubbles in water that briefly glow as hot as the sun. When shrimp snap their claws underwater, they produce sonoluminescent flashes that, according to some scientists, really can induce small amounts of nuclear fusion. This principle may someday be used to trigger fusion in cheap, tabletop reactors (Mr. Fusion, anyone?), but more importantly it lends credibility to the idea that animals really can produce nuclear reactions to partially petrify their enemies. If looks could kill, we should at least hope they'd kill in interesting ways!

Sources:
Bullfinch, Thomas: Bullfinch's Mythology: The Age of Fable or Stories of Gods and Heroes, 1855

Encyclopedia Britannica 2004 Ultimate Reference Suite: "basil," "basilisk," "cockatrice," "cobra," "mongoose"

Stevens, Serita Deborah and Klarner, Anne: Deadly Doses, a writer's Guide to Poisons, Writer's Digest Books, 1990

Neuschl J., Kacmar P.: "Acute oral toxicity of bentazon in pheasants and rabbits and the clinical symptoms of poisoning," Vet Med (Praha). 1993;38(2):115-21.

Old Testament of the Bible: Isaiah 11:8, 14:29, 59:5, Jerimiah 8:17

Davis, Gailey, and Whitten: Principles of Chemistry, CBS College Publishing, 1984

The Internet Movie Database (www.imdb.com): "Basilisk: The Serpent King"

"Basiliskenhaus, An old Viennese legend," www.wcities.com/en/record/,89128/94/record.html

Wikipedia (en.wikipedia.org): "basilisk," "cockatrice," "amber," "ambergris," "sonoluminescence"