“Since the vile Plante’s Deceased Hoste is not technically a Part of its Anatomy, any attemptes to Kill the Monster using regular methods is likely to prove Futile, especially that of Beheading the Creature. It seems to regarde its Head as a most Unnecessary part of its Composition, and thus as it moves its Head exhibits a frightening lacke of Expression, and lolls in a way most Unpleasant to observe.”
Long sieges can be a trial for both sides. For the beseiged especially, finite ammunition supplies always pose a problem - except when the ammunition can reproduce…
"Many strange things may be seen in the Great Swamps, not all real. But I tell you, there was a ship and it was real! Well it was old and all sails torn and had many holes in the hull... but anyway it was hundreds of miles from the Sea! How it came to be there, I can only wonder..."
(If it is not a hallucination, may be inhabited by wererats.)