The Horror of Lannock Hill

From the Introduction

The Horror of Lannock Hill is a short adventure for four 10th-level characters. The party may consist of any mix of classes, although at least one member of the party should be capable of handling a difficult melee combat. The adventure is pretty straightforward, and it should provide a good challenge for characters from 8th to 10th level. It can be set in any campaign world.92) instead of the relatively innocuous natural forms presented below.