Cha'Dylan
From DDwiki
A partially explored subdungeon that contains an island of blackspace with a monster icon. The outermost layer of blackspace is explorable (about 40 tiles total), but reveals impassable terrain immune to ENDISWALL. WONAFYT allows you to summon the monster, which has 2 life, 50 damage and Death Protection(7). When killed, it drops a Sensation Stone.