Oh, No You Don't!

There is a rock at 60.76 56.90 that spawns a resting Roaming Shredclaw. We have found that engaging it in combat has consistently caused the Opportunistic Harrower to spawn and grab it.

• 
  
• We were unable to make it spawn attacking any other mobs during the 15 minutes we spent testing/attacking mobs in the area.
• 
  
• We can also confirm that if you don't actually tag the mob before it's picked up, you do not get credit for the achievement upon landing at the destination.
• 
  
• Teammate tags do not count for the above, it's all personal tags..
• 
  
• Losing sight of the Opportunistic Harrower will typically void the process and you will need to start again.
• 
  

Check screenshots for visual of the rock.
/way 60.76 56.90 Roaming Shredclaw resting on a rock

Update March 3rd, 2026: There is another mob that triggers this near the portal that first brings you to the voidstorm. It spawns on several permanent corpses at 35.01 59.79. This one is actually a Hungry Kilivore. This mob is phased once you complete the quest Dancing with Death
As I already have the achievement I was unable to confirm that it awards it, however I was able to follow it back to the same Nest as the previously spawned one.

Just got the achievement. I pulled random mobs around 61, 57, it appeared as soon as I pulled the second pack and grabbed one of the 3 Roaming Shredclaw on and around a stone at 61.35, 57.17. I then killed the remaining mobs, flew towards it and arriving at its nest at 43.79, 51.69 (where the rare Screammaxa the Matriarch spawns) I got the achievement.

/way #2405 61.35, 57.17 Roaming Shredclaw
/way #2405 43.79, 51.69 Nest

It seems you have to tag Roaming Shredclaw.
If you only body pull or are grouped with someone else tagging it does not trigger the achivement