Wavestone Keep

From the publishers blurb: Fear the waves, the tides and the sea itself! A fearsome tower of stone roams the oceans, delivering its deadly cargo of lizardmen wherever it happens to land! This is a small dungeon adventure, with an included map, introducing a floating, teleporting chunk of stone that wanders the seas collecting victims and treasures. It is designed for Old School Essentials. This adventure is desinged for parties of up to level three.