From publisher blurb: (SPOILER) I guess I'd never noticed the 'thoul' listing in the B/X monsters. Chalk that up to incomplete reading comprehension, or something. And, I don't think I've seen them employed in the adventures I've perused. So, time to drop them as backup dancers in some B/X-style song and dance, this one taking place in caverns accessed via a tidal marsh, where someone is up to nefarious deeds.