Scooby-Doo! A States of Matter Mystery: Revenge from a Watery Grave is an educational book in the Capstone series as a part of the Scooby-Doo! Solves It with S.T.E.M. line.
Summary[]
Is that fog or is it a ghost? Scooby-Doo and the gang are on the case to find out whether that spooky ghost is to blame for the missing yachts at the harbor. Using their knowledge about states of matter and solids, liquids, and gases, the gang is ready to reveal the solid truth about that gaseous ghost thief!