IT: Welcome to Derry episode 2: Why is Dick Hallorann in Derry?

Warning: Contains possible spoilers from Stephen King's IT novel.Another episode into IT: Welcome to Derry, and the Stephen King crossovers are quickly stacking up.Along with the clue-filled opening credits and the numerous IT references in the first episode, episode 2 widens the scope, introducing a character best known from a different Stephen King novel entirely.So who is it, and where do we know them from? We've broken it down below.SEE ALSO:Every single Stephen King movie adaptation, ranked