Tarachnid Creeper

[item=189466] is a protoform synthesis mount.

Schematic can be found inside a small archive within Endless sands area. Open the archive and loot the schematic.
After bringing the schematic to Protoform Repository you will learn how to create [npc=359402] mount.

Resources list:

• 
  
• 450 x [item=188957] - drop from mobs all around Zereth Mortis
• 
  
• 1 x [item=189177] - drop from [npc=180746]
• 
  
• 1 x [item=189152] - drop from [npc=178508]
• 
  

[item=189466] location - https://youtu.be/DaYGJNr-qfY

/way 62.85 22.01 Schematic Tarachnid Creeper

To unlock protoform crafting:

Complete chapters 1,2 and 3 of Secrets of the First Ones zone campaign.
Research [order-advancement=1931] and complete [storyline=1285] questlines.
After daily reset complete The Lost Component + A New Architect quests to unlock [spell=366367].
Complete Protoform Synthesis quest to unlock [spell=366368]

To get [item=187678] you need to find [item=189466] in Zereth Mortis and bring it to the Synthesis Forge*, then collect reagents for the craft

How to get Schematic:

1. 
   
2. How to get video: https://youtu.be/xPmT1eljnak
3. 
   
4. Location map: https://i.gyazo.com/2dca95cfcdf23fc5f589baeea8ea37f0.jpg
5. 
   
6. What to look for Img: https://i.gyazo.com/b111a55f1e95151701f9ad1b984c78d9.jpg
7. 
   
   
8. [object=375270] in Endless Sands
   Inside the building on the floor
   /way 63.02 21.51 Tarachnid Creeper
9. 
   

Resources required to craft (all of them are zone related):
450x[item=188957] - drops all over the area
[item=189177] - drops from [npc=180746] rare & requires 2 players to activate
[item=189152] - Can buy on AH or farm from specific mobs (check dropped by section)

*Prerequisites to unlock the Synthesis Forge to turn in the schematic and craft the Mount:
Complete 3 parts of the main campaign in the Secrets of the First Ones Forming an Understanding
Complete a [order-advancement=1931] upgrade of the [npc=181397]
Complete Protoform Synthesis quest to craft pets / Finding Tahli questchain to craft mounts
More detailed info can be found here: Synthe-supersized!
/way 70.18 28.60 Servitor Interface (Mounts Forge Location)
/way 61.97 58.93 Protoform Synthesis Forge (Pets Forge Location)
Right now you will need to complete the prerequisites to interact with the forge and turn in the schematic quests

The schematic was not on the ground, but it appears I did not activate the Mercurial Concordance.

After I activated the Concordance the schematic was there.