Chestnut
Source: Drop. Chestnut once found an acorn larger than he was, ate the whole thing, and doubled in size. It's a good thing he didn't eat a Trunkalumpf. Critter type. is found on at 49.43 62.90 as an standing on a rock near a tree. To obtain it you need to find an on the ground nearby, interacting with one will give you a buff called .
The 
Chestnut is a battle pet dropped from the Acorn Harvester treasure in Thaldraszus, obtained by picking up a nearby acorn and interacting with the squirrel NPC.
Guide awaiting review
Travel to Thaldraszus
Head to Thaldraszus, west of Tyrhold, and locate the Acorn Harvester standing on a rock near a tree at 49.43, 62.90.
Pick Up a Nearby Acorn
Search the ground around the Acorn Harvester for one of three acorns located at 49.38, 62.66, at 49.87, 63.13, or at 49.79, 63.21. Interact with one to receive the Acorn buff.
Interact With Acorn Harvester
With the Acorn buff active, return to the Acorn Harvester at 49.45, 62.91 and interact with it to receive Chestnut. Note that the Acorn Harvester may have a cooldown if another player recently fed it.
Tips
There are three acorn spawn points around the Acorn Harvester, so if one spot is empty, check the others at 49.38, 62.66, 49.87, 63.13, or 49.79, 63.21.
This treasure counts toward the Treasures of Thaldraszus achievement.
