Mtx pet is a glitch item given to the player when the game forces the player to pick up their pet while having a pet from Solomon's General Store following them. Pets from Solomon's General Store are summoned through the pet interface, and can not usually be picked up. Every interface pet from the store has an item object in the game configuration as "Mtx pet".
The bug that caused the mtx pet to be picked up was fixed in the 3 January 2013 Patch Notes, making the item unobtainable.
Having a Solomon's Store pet summoned could lead to picking up the mtx pet in several situations, including the following:
- Doing Agility courses
- Going through the wheat in Puro-Puro, with the chatbox message "Your little friend can't make it over the obstacle ... so you pick it up"
- Attempting to do the jester act during The Fremennik Isles
- Creating a new hot air balloon route
- In the Rat Pits, changing pets before the fight