Decrepit Cave

From HGWiki

The start and end point for the Legendary Level Beholder area Zorbgot's Hive, talk to the beholder resident Bob for more information about the situation.

Note that the zone line for Zorbgot's Hive is not clearly visible. Walking about halfway into the cave will transport you to Zorbgot's Hive with little warning, which can be a nuisance if your party is/was waiting to teleport to you. Have your party teleport to you as soon as you enter.