Thumpers can on very rare occasion spawn inside caves, unable to move around - Only turn. This seems to only happen if the player is inside said cave. A Tusk Thumper being stuck, only able to turn, inside one of the caves in the Plains of Eidelon.
How do I farm Korrudo?
Korrudo's main blueprint can be obtained from defeating a Tusk Thumper Bull or Tusk Thumper Doma in the Plains of Eidolon.
Do thumpers spawn at night?
Nop, they don't spawn at night. If you're fighting one when night falls, it won't despawn, but once the alarm rings, you can go get a break. On a side note, after painfull hours of farming, we have noticed failing and restarting your bounty reset spawns, and you can chain thumpers way faster.