What separates a skeleton from a lich — and does immortality inevitably make you evil? In this episode of FGGGbT, the Brain Trust — Daniel J. Glenn, Dr. Michael Dennin, and Ben Siepser — tackle one of the most ambitious projects of the season: building a complete taxonomic classification system for the undead. Using six core categories — physical presence, soul spectrum, voluntary vs. involuntary transformation, dead-then-reanimated vs. transformed-while-living, life force alteration, and sensitivity to pure things — they systematically break down skeletons, zombies, mummies, ghosts, banshees, liches, and vampires with the rigor of scientists and the enthusiasm of lifelong D&D players.

Along the way they debate whether mummies are just high-quality zombies, whether a ghost can choose to stay or is forced to linger, and whether the vampire or the lich is the true apex undead predator. They also tackle the big philosophical question at the heart of all undead lore: does immortality inevitably lead to evil? Ben Siepser’s argument — that anything divided by infinity equals zero, making all moments meaningless — might just be the most elegant explanation for why every lich eventually goes mad and every vampire eventually stops caring about the living.

Whether you’re a dungeon master building your undead roster or just someone who’s always wondered what actually separates a mummy from a zombie, this episode has the answers.