Round about the second or third time that one of the shape-shifting Parasytes of Hitoshi Iwaaki's sci-fi horror manga transformed to separate some poor slob's head from their body, I began to think of John Carpenter's 1982 movie remake of The Thing. In that flawed, but entertaining, low-budgeter, there's a scene where one of the movie's stranded Antarctic scientists appears to have suffered a heart attack, leading the base physician to attempt to revive him with defibrillator paddles. Unfortunately for our doc, the seemingly dead human is an alien whose torso quickly (courtesy fx great Rob Bottin) shifts into a giant fanged mouth that severs both of the would-be caregiver's hands. It's the kind of bloody visual moment that's make or break for the audience: either you accept it with a whoa! and perhaps a small chuckle – or you drop out of the movie altogether.
Same goes with Iwaaki's horror tale. Twenty pages into the first chapter, we get a scene where a parasite-controlled husband chomps off the head of his wife. In it, the no-longer-human approaches his apron-bedecked missus, and as he holds onto her shoulders, his head splits open, looking at first like some carnivorous flower than like some Lovecraftian sea creature with fangs and a plethora of eyes. As he bites and removes his mate's pate, his own head appears as large as a watermelon – an image both grisly and comically cartoonish. Hey, the reader wonders, where's the guy's brain located, anyway?
Physical transmogrifications, both horrifying and comic, figure prominently in Parasyte, courtesy of an untold number of wormy creatures that mysteriously land throughout Earth to take over human hosts. Entering their victims' heads through the ear canals while they're sleeping, they eat their victims' brains and take over the bodies. When self-described "good-hearted high school boy" hero Izumi Shinichi is chosen by one of these creatures, though, there's a small glitch. Because the boy is lying in bed wearing earphones, his would-be feaster is forced to find another orifice into the kid's head. Before this can occur, however, Shinichi wakes and is horrified to see what appears to be a large snake in his futon. The parasite bores into Shinichi's palm and attempts to reach the brain by going up his arm, but our hero holds it back with a tourniquet. As a result of this quick-thinking act, the creature is unable to get to our boy's skull before it matures inside his body. ("I matured before I could eat your brain," the creature later nonchalantly notes. "Such a shame.") Instead of being able to commandeer his host, the parasite can only control Shinichi's right arm and hand.
The parasite-of-unknown-origin soon begins communicating with our hero, spouting eyes and mouths on his fingertips or palms to suit his purpose (and presumably small vocal chords inside to allow it to speak). The creature, which takes the name Migi (for "right"), is a calculatedly comical looking creation, and it's clear that at one level he's meant to stand in for the awkwardness of young adolescent body change. In one early sequence, for instance, the curious parasite hand tries to give Shinichi an erection as he stands before a public urinal to see what the experience is like. Our good-hearted hero is not at all amused.
Writer/artist Iwaaki plays his hero's adolescent travails for knowing chuckles, and there are plenty of moments that read more like high school comedy than they do terror. Which is not to say that Parasyte stints on the shape-shifting horrors: to remind us of the ever-present peril, we regularly cut to other host bodies as they attack and feed on their human victims. To Shinichi, this act smacks of cannibalism, though the non-human Migi doesn't see it that way. To its "mind," singly focusing on devouring on humans is natural and amoral. Unlike humans, who seem to be willing to "eat anything," his appetite appears to have a specific natural function: to regulate and thin out the human population before it completely trashes the planet.