Eddie Kaspbrak’s worst fear in Stephen King’s *It* is a disease-ridden leper. It takes this form because Eddie is a hypochondriac who has been conditioned by his overprotective mother to believe that he is seriously ill, especially with asthma.
When Eddie encounters It beneath the Neibolt Street house, the creature appears as a rotting, diseased man covered in sores. The apparition is not merely a random monster: it embodies Eddie’s fear of contamination, illness, and physical decay. This is why “a leper” is the canonical answer, rather than a generic fear of germs or hospitals.
A common mix-up comes from the novel’s climactic confrontation, when It takes the form of a giant spider. That spider-like shape is It’s closest physical approximation of its true nature and is associated with the final battle involving the Losers’ Club, but it is not Eddie’s personal worst fear. In the 2017 film, Eddie also encounters a similarly diseased leper, preserving the key detail from the book.