Some scientists believe that Trichoplax, with its stripped-down body plan and easy-to-manipulate genome, could be a useful model organism for medical researchers. It’s especially intriguing because it breaks the rules that most lab animals follow: Unlike mice or fruit flies, Trichoplax has an indefinite life span, rapidly heals, and never—so far as scientists can tell—develops cancer. “We’re always trying to figure out what the rules are,” says Billie Swalla, a biologist at the University of Washington who studies regeneration in weird animals like acorn worms, which can regrow their heads. Studying rule breakers like Trichoplax, which can tear themselves apart and heal in minutes, could yield insights into the treatment of human injuries like damaged spinal cords, she says. Adventurers who journey to the Feywildmighthappen upon a pixie's glade when seeking out a spot to take a long rest. There, they might hear the giggles of these delicate creatures and have harmless pranks played on them. If the party shows that they have a good sense of humor, pixies might reveal themselves and be more than willing to offer aid. Even if placozoans are not the oldest animals, they’re still some of the weirdest. Trichoplax’s genome, published in 2008, contained a surprising twist, Athula Wikramayake, a developmental biologist at the University of Miami, says. Despite having the simplest bodies of all animals, placozoans carry many of the same genes as humans do, including numerous genes involved in building brains and other complex organs, like those in the digestive system. Placozoans contain far more genetic complexity than scientists ever guessed, Wikramayake says. “The question is, what are they doing with it?”

Hags can really shine — er, glower — in combat. A sea hag’s Death Glare is terrifyingly powerful against low-level adventurers. It forces a frightenedcreature to make a DC 11 Wisdom saving throw or drop to 0 hit points on the spot.Dungeon Masterscan use the boggle for either a fun side adventure or as a way to introduce the party to larger plot points. A boggle could steal an object from the party out of a desire to cause mischief and lead them on a slippery chase through a busy city. A group of bogglescould play a hilarious game of keep-away, creating Dimensional Rifts to pass a stolen item amongst themselves and filling tight corridors with slippery oil.

Shifting through the party's camp as fast as the wind, they tied the shoe strings of the heaviest character together. Then one of the feys took a dagger from the camp to distract the guard, so the other quiskling can move all important adventuring gear in the guard's bag. For elegant finish they took a beautiful ring from one of the sorcerers (the party's ring of jumping, gifted to them by two rogue kids) and braided the hair of two characters. Prakash hands it to staff scientist Hazel Soto Montoya, who puts it in the Igloo cooler with reddish seawater she has filled at the marina. Soto Montoya is currently studying the symbiotic bacteria that live in Trichoplax’s body, so she wants to re-create the ecological milieu in which they found it, red tide and all.Night hags, however, are strongest when they're aware of their enemies. They can enter the Ethereal Planeto inflict nightmares on a creature, lowering their hit point maximum and depriving them of the benefits of a long rest. Using hags in your game

While the current selection of hags top out at a challenge rating of 7, a coven of three hags vastly increases the difficult of an encounter (see "Hag Covens" below). Hag Covens Pixies have a whopping 1 hit point. But their innate ability to turn invisible, 15 AC, andselection of spells make them difficult to catch. Of course, pixies are social creatures who live together in groups, so turning a dagger to one pixie could mean being swarmed by a dozen others. Using pixies in your game

I n Prakash’s lab, located in the leafy bioengineering quad at Stanford University, he and his graduate students, postdocs, and lab technicians are less concerned with figuring out where Trichoplax fits into the story of animal evolution than how it manages to live such a full life—creeping along the ocean floor, sensing its surroundings, eating algae—with such minimal equipment. “Where does behavior come from in a system that doesn’t have neurons?” he asks. He’s also interested in the shape-shifting animal’s basic physical properties: “Is it a liquid? Is it a solid? Is it something in the middle?” A D&D party might encounter a hag after investigating a case of missing babies or afterdiscovering a town that has been torn apart by gossip, false accusations, or even nightmares.A solitary green hag or sea hag can be the primary villain for a 1st- or 2nd-level adventure. Night hag: Once creatures of the Feywild, night hags were exiled to Hades. These creatures befoul all good things, turning love into obsession and generosity to selfishness. A lthough he’s one of the youngest scientists to fall for Trichoplax, Prakash is far from the first. The weakness for the amoeba-like creature often begins unexpectedly, when it squirms into a researcher’s field of view. The German zoologist Franz Eilhard Schulze, who discovered the animal, spotted it as it crept along the interior of a saltwater aquarium meant for other species. Smith saw her first Trichoplax when it glided across her microscope slide while she was examining some sea sponges. While Prakash agrees that the animal holds great promise for biomedical research, his pursuit of Trichoplax is about more than its practical applications. “I also study it for its beauty and elegance,” he says.