The Haunted Wall is a cubic building-block with white and pink stripes looking like an old wallpaper.
All its 6 sides look a little different, and the block can be rotated into all directions by pressing and holding R (as the default key) while moving the mouse.
These non-aggressive ghost creatures only spawn in complete darkness at (ingame)night (starting a little later than 10:43 PM) and cannot be tamed, only killed. Ghosts usually flee from player characters and do not defend themselves.
Ghost creatures can be spawned on a Mob Spawner too, but in that case these non-tameable creatures won't drop anything at all when being killed, except for the stuff that players themselves have provided to the inventory of the Mob Spawner for the first creature to spawn.
Haunted Walls can also be crafted in your Crafting Menu (default key "Q") or at Crafting Tables (that still exist in worlds created before R22 on September 16th 2015), but only after the crafting-recipe has been obtained from ghost creatures during the Halloween event.
It is possible to obtain and learn such a recipe when visiting other players on their worlds. With update R46 in September 2017, the exploit that allowed rare Holiday Recipes to be learnt via Adventures was fixed.
After learning this crafting recipe by right-clicking it in the inventory or dragging it over the character's model on the right side of the inventory, it will be permanently added to the crafting menu and as a rare recipe it will also "carry over" (be known) on all other Creativerse gameworlds after learning it.
To craft 8 (blocks of) Haunted Walls at once, you'll need
- 2 (blocks of) Wood (except for corrupted wood) or Logs of any kind, taken from trees, found on the ground of many surface Biomes or in Wood Treasure Chests at night
- 2 Bones that can either be made from blocks of Fossils in a Processor or be obtained from nearly all Creatures either by killing them or taming them, feeding and then harvesting from them