When a child is super angry and does everything in its will to succeed in their goal.
Bryson entered Gorilla Parkour Mode because he got no candy for lunch.
When a child gets so angry that they can risk their existence to achieve their original goal. This normally results to violence, insane parkour skills, and in fear among others.
Jacob wanted to play with a piece of plastic but he couldn't so he entered Gorilla Parkour Mode.
Gorilla Parkour Mode is when a person gets really angry and gets a stamina and starts chasing a person being annoyed to them.
When I was annoying Bryson he went Gorilla Parkour Mode!