Theory that Shank is a Plague Spread by Consumption
So in 162 Arnold get hungry right before running into Shank
It nothing out of the ordinary, Arnold’s a growing boy after all.
Then when Diggory is fighting Shank in 198 they start hungering for meat.
Now Diggory doesn’t even have a stomach and, as stated, has ‘never hungered before’, so fact they suddenly are is very noteworthy. The cause: Shank’s breath. Shank’s breath made them hunger for the first time in their life. Specially, hunger for meat.
Following Shanks beheading the Wickers eat him, which is weird (Bonus story 200, ep 205). I know they think they’re honouring Josh and celebrating their revenge, but what if it was more than that. What if Shank causes people to want to eat him. And what happens once you eat Shank? You become Shank. And so Shank multiplies.