It's Nightmare Fuel, up to eleven.
- Mantis shrimp the size of eighteen-wheelers, spiders that dwarf saber-toothed cats, worms that burrow into your eyes, trees that drink your blood... this is arguably the most horrific Lost World ever created.
- Not even heavy armor can hold out long against some species.
- Henders Isle. It's a nonstop orgy of killing and eating where you're lucky if you live for a few minutes after setting foot there unprotected (and even protection is just delaying the inevitable). Everything isn't just trying to kill you, everything is trying to kill everything!
- To be more precise, everything is trying to devour everything alive, because if they actually took the time to wait for something they're attacking to die, the teeming masses of other predators nearby would beat them to it (and probably eat them while they're at it).
- In an effort to test out the island life's capabilities, the crew sends out a mongoose- a carnivore renowned for its resilience and invasive behavior-into the island jungle with a critter cam. You want to know what happened next? It ends up ravaged by a rat-like animal in the span of two minutes of exposure. The crew then pit several other non-island animals against captured island species, and the island species win all of them.
- Also notable are the plants which nurture seabird chicks. Doesn't sound so bad, right? Except that the plants ate the chicks' parents, and nurture the chicks so they'll come back to breed and be eaten in turn.
- Sadly, that species of seabird is probably doomed to extinction, despite being one of the island's only harmless inhabitants. Even if a lot of young not-yet-mated adults were out fishing when the island was nuked, they've probably lost the instincts to care for their own chicks, having become too dependent on the Henders trees to raise their young normally.
- The relatively nondangerous species (including species that can kill you, but choose not to, like Hender and the other Hendropods) in this ecosystem can be counted on one hand!
- It's theorized (with good reason, as the most charismatic Henders creatures vaguely resemble them, and giant versions inhabit its rivers) by some of the characters that mantis shrimp evolved on Henders Isle (which might explain why they're so badass)
- In the sequel there's a Puppeteer Parasite octopus which kills its victim, latches onto its nervous system and limbs and disguising itself as the host species. It has a bit of difficulty with people however, as humans walk upright, so when it latches on a human it stumbles around awkwardly on all fours, invoking serious Uncanny Valley.
- Henders Island may be the most horrific Lost World imaginable, but Pandemonium probably comes in at a close second. Giant sea spiders, puppeteer octopus, car-sized cooperating jellyfish, linked chains of carnivorous centipedes, flying cephalopods that literally rain venom, colonies of hippo-sized man-eating crustaceans, and apparently that's only the tip of the iceberg. If it weren't for their vulnerability to sunlight, then the world would have a second Hender's Isle in its hands.
- It doesn't help that Pandemonium's wildlife have a resistance to saltwater, something the Hender's Isle species almost lack, and they're shown a few times actually holding their ground against them, something other land animals besides humans have difficulty doing.
- The implications of the incredible danger the Henders organisms pose. The fact that if even one mite-sized thing got off the island would mean the death of pretty much everything on earth within 20 years is absolutely terrifying.
