IT: Welcome to Derry season 1 episode 4 introduces Pennywise's origins in the cursed town of Derry, Maine, merging historical trauma with the memories of the region's Indigenous people. While hints about the clown's origins appear throughout the previous episodes, episode 4, The Great Swirling Apparatus of Our Planet's Function, establishes how the monster's origins are woven into Derry.Disclaimer: The following article contains spoilers for IT: Welcome to Derry season 1 episode 4. Reader's discretion is advised.Central to this reimagining of the creature is the Galloo, the name given to the entity that would later be known as Pennywise by the local Shokopiwah tribe. Through a psychic journey undertaken by Dick Hallorann, the episode introduces viewers to the legend of how the Galloo traveled to Earth and how the "cage" of the creature came to be located in Derry. A run-down house on Neibolt Street in Derry appears to serve as a gateway to the monster's cave located underground.IT: Welcome to Derry season 1 episode 4: The ancient tale of the Galloo explored View this post on Instagram Instagram PostTowards the end of IT: Welcome to Derry season 1 episode 4, Dick Hallorann enters the mind of Taniel, a member of the Shokopiwah tribe, and brings forth a mythic origin that Taniel's younger self experienced. According to legend, Taniel's younger self heard, millions of years ago, that an evil spirit, later referred to as the Galloo, was trapped inside a falling star.When it crashed, it broke open, and the spirit began roaming over land. The tribe made a dagger from a shard of that meteor, and it became their only form of defense against the being. When settlers came and invaded the Western Wood, the Galloo became stronger by feeding off their fears.The tribe recognized the threat and was able to gather 13 shards of the meteor, burying them around the forest to create a barrier. In adult Taniel's memories, he tells Hallorann to go follow "tunnels under the old well," which leads to a decaying house on Neibolt Street.The significance of that house, now known as the Well House, lies in its connection to hidden underground tunnels that are linked to the shard burial. This means that the house is not simply creepy but is the threshold of the Galloos' containment in Derry.Also read: IT: Welcome to Derry creators react to Stephen King's praiseHow does Pennywise haunt the kids in IT: Welcome to Derry season 1 episode 4?(L-R) Blake Cameron James, Clara Stack, Amanda Christine, Matilda Lawler, and Arian S. Cartaya speak onstage at the TV Sidebar presented by Deadline screening of "IT: Welcome to Derry" Q/A (Image via Getty)In IT: Welcome to Derry season 1 episode 4, one of the frightening events due to Pennywise's ongoing manipulation happens to Will, who goes on a fishing trip with his father, Leroy. Will recounts it as a deeply traumatic experience as Pennywise appears as Leroy, burned alive, and drags Will underwater.In other developments, the children's attempt to provide tangible evidence to support their reports of paranormal activity collapses when they show Chief Bowers the pictures they took in the graveyard. The only figure that seems to be in Will's picture is Pennywise, whom Chief Bowers disregards as a statue.The children begin to suspect their fears are being brought by Pennywise before it begins hunting them. They suspect that Pennywise is spiking their fear hormones, such as adrenaline, to feed on and grow more powerful from it. Lilly, as a response, proposes they take some valium from her mother's medication as a way to offset their fears, a desperate plan to mitigate the monster's power.What happens to Marge in IT: Welcome to Derry season 1 episode 4?A still from the episode (Image via Instagram/@it_official)The plot surrounding Marge moves into the realm of body horror in IT: Welcome to Derry season 1 episode 4. Under pressure from the Patty Cakes, she decides to play a vicious prank to humiliate Lilly. But as she devises her plan, Pennywise exploits her deepest fear, which is revealed during a biology lesson about parasitic flatworms.Marge begins to hallucinate that her eyes have morphed into long, pulsating stalks that have bulged and extended outward from her head, resembling the worms in class. In a frenzied panic, she tries to gouge out her eyes by any means possible. This gruesome act leads to her inflicting physical harm on herself.When other students run into the room, they see bleeding Marge, with Lilly (who was trying to help her) clutching sharp tools, appearing to have attacked her. This horrifying, body-horror scene encapsulates the ways Pennywise preys upon individual fear and isolates Marge. IT: Welcome to Derry season 1 episode 4 is available to stream on HBO Max.