Bunsen fails to take notice of the gorilla behind him.
The Gorilla Detector is a device presented in episode 116 of The Muppet Show as the latest invention from Muppet Labs by Dr. Bunsen Honeydew. The invention itself is in the shape of a gorilla's face, with lights for "eyes" and a prominent snout and brows. The prop is based on the head of Mechani-Kong from the 1967 Japanese film King Kong Escapes.
The device is intended to sound an alarm when a gorilla is approaching; Bunsen observes that many people's vacations were ruined when they were eaten by gorillas. During the demonstration, what appears to be a gorilla enters the lab and proceeds to destroy equipment. Bunsen placidly insists that, as the Gorilla Detector has not sounded, the creature cannot be a real gorilla. The alarm finally goes off, but only after the gorilla has attacked the good doctor. The gorilla stomps on the detector, destroying it in the process.
In 2002, a replica of the Gorilla Detector was included with the Muppet Labs Playset from Palisades Toys. It was later featured as a sticker in a 2012 LittleBigPlanet add-on pack, and as a decoration in My Muppets Show.
The Muppet Mobile Lab has a lever on it labeled "gorilla detector."