He was originally invented by Romeo as part of a plan to infiltrate HQ. Romeo intentionally made PJ Robot cute and friendly, knowing the heroes would like him and take him to HQ. However, PJ Robot began to genuily like the PJ Masks too, and eventually doublecrossed Romeo to join them.
PJ Robot has the ability to hover above the ground, but additional details of its ability are currently unknown. It is presumed that PJ Robot can fly at high altitudes and speeds because of its wings.
In "The Mountain Prisoner", it's revealed that PJ Robot has at least four weapons installed in him, and can fight alongside the PJ Masks if needed.
PJ Robot cannot speak. Instead, he expresses his emotions by changing the digital face on his head. He is very friendly and energetic.
PJ Robot is shaped slightly like an egg and is white in color with a red trim design around its body and wings. It wears white gloves on its hands, and it has a clear dome for a head, with an aqua-colored digital face.