THE FURNACE MONSTER!

Hello everybody! Sorry I haven't bloged yet but here goes . Why is Zinkoff so afraid of the Furnace monster? I mean what's so scary about it any way? It all happened on chapter 14 on page 84.It starts at the part where it says ''In respect,however,he is like almost all children .He fears the darkness of the celler . And even then,it isn't strickly the darkness that he fears .It's what dwells in the darkness the Furnace monster.'' I mean mean like what is so scary about that?