The Rusty Mechanocrawler is a new mount added in patch 8.2 of World of Warcraft: Battle for Azeroth. It is tied to the Mechagon zone, and it currently seems that it drops from the Anarchnoid Harvester rare mob found just outside of Bondo's Yard in Mechagon (coordinates: 52.42 , 40.87).
There are some theories that it can also drop from other rare mobs in the zone, but this is not confirmed just yet. We will just have to wait a bit and see, and this guide will be updated once we get confirmation or debunking information about this. If you had this drop from any other source, please let us know in the comment section below.
Like other rare mobs in BfA, you can kill them once per day for a chance of obtaining loot from them, so be expected to try to kill Anarchnoid Harvester once every day if you want to farm this mount.