At the head of the planarian there is a brain under the eyespots. From the brain, there are two nerve cords, which connect at the tail. There are many transverse nerves connected to the nerve cords, which make it look like a ladder. With a ladder-like nerve system it is able to respond in a coordinated manner.
Adventure mode. From Diablo Wiki. Adventure Mode or AM is the primary end game type of game mode introduced into Diablo 3 in the Reaper of Souls expansion pack. Campaign Mode or Story Mode is the other primary game mode, where players must progress through the acts in order, complete quests, talk to NPCs, watch cut scenes, etc.
Inside the Unknown Depths. Fighting in the Unknown Depths. The Unknown Depths is a one-level dungeon found in The Terminus in Act II of Diablo III. Player(s) must cross it and open the Shadow Lock in the end, then leaving through the portal.