To attach a petpetpet you need to have the pet owning the petpet you want it to attach to as your active. You then need to refresh your inventory. It may take a few attempts, and you risk a bad RE (such as the Pant Devil).
You can learn to draw the Mootix here.
You play Harry the Mootix, as you lead him through rings, and onto a target. You can play here.
In this game you throw a Mootix Ball, and see where it lands. You can play here.
You play a Cooty Commander trying to destroy the Mootix paratroopers before they hit the ground. You can play here.
There are around 35 items associated with the Mootix such as:"Mootix Parachute Toy", "Mootix (TCG)", "Springy Mootis Toy", "Mootix Pen" and "Mootix Ruler".