This chapter maps out the central paradigms for conceptualizing the monsters of American horror, marking their inextricability from politics and moving toward identifying the principal forms of monstrosity in the early twenty-first century. Monstrosity has been defined as impure and abject, existing on borders, not categorizable; the incarnation of “otherness,” typically racial, gendered, sexual, or class; and a terrifying reflection of the “self,” as the monster has increasingly become an avatar of “normality” rather than what threatens it, embodying dominant rather than marginalized social structures and ideologies. Most recently, monsters are being generated by scientific explorations that insist on the thoroughgoing entanglement of life, the ways in which the “human” is not singular, not exceptional, but rather symbiotically entwined with nonhuman life. This form of horror is adeptly exploited in Silvia Moreno-Garcia’s 2020 novel Mexican Gothic, about an entangled fungus and a colonial family.