What’s the Deal With Hallorann’s Terrifying Box on ‘It: Welcome to Derry’?

In the most recent episode of It: Welcome to Derry, we saw various characters—heavily armed Air Force guys, a member of the local Indigenous community wielding an alien dagger, and a group of awkward young teens—slip into the sewers under 29 Neibolt Street in search of you-know-who. We know they’re chasing an entity that delights in taking the form of Pennywise the Dancing Clown; at this point in Welcome to Derry‘s storyline, however, nobody’s quite certain what they’re…