Some of the comments posted to this video are funny. One of my favourites is, "Yep, lock the door and he comes through the window, lock the window and he jumps the fence..." It's funny because it's true!
The video is titled as an ACT metaphor though it may not be clear. Controlling Brian is a metaphor for controlling unwanted thoughts and feelings. That struggle for control will inevitably fail. Brian is a window-climbing, fence-jumping, determined creature. The struggle to control takes away from living fully, diverting effort from actions which serve what we value.