Batalisks aren't renewable in Hamlet only worlds. This makes Cowls unrenewable. Cowls can't be repaired by sewing kits and can also not be fueled by glowberries. This could easily be avoided by making Vampire Bats have a chance to drop Bat Wings or by making them refuelable like Moggles.
Steps to Reproduce
get a cowl and try to refuel it
This issue has been fixed in either a future version or updated in a previous version.