Stowaway Rat
Source: Pet Battle. In the lean times when adrift at sea, the sight of a rat was a welcome one. Critter type. I have been getting them as a second pet while farming the Crimson Geode
The Stowaway Rat is a wild battle pet found in Deepholm, obtained as either a primary or secondary spawn near the crashed ship area.
Guide awaiting review
Travel to Deepholm
Head to Deepholm and locate the crashed ship area, which is the only confirmed zone in the game where Stowaway Rats appear as primary spawns. Spawn numbers here are limited.
Battle pets near the ship
If no Stowaway Rats are visible as primary spawns at the ship, engage other battle pets in the surrounding area — Stowaway Rats are known to appear as secondary pets in those battles, including near Lorthuna's Gate.
Watch for rare quality
Stowaway Rats can appear at common quality first, with rare quality versions showing up after several additional battles in the same area, so continue fighting local pets until a rare one surfaces as a secondary.
Tips
Crimson Geode farming in Deepholm is a confirmed source of secondary Stowaway Rat encounters.