During the first season of The Muppet Show, Bunsen Honeydew presented the Muppet Labs segments by himself; Beaker was added as his lab assistant from the second season on. Beaker has googly eyes, a shock of red hair, and a drawbridge mouth. He was originally puppeteered and voiced by Richard Hunt until Hunt's death in 1992, when the role was taken over primarily by Steve Whitmire.
Dr. Bunsen Honeydew is a Muppet from The Muppet Show, performed by Dave Goelz. He is a bald, bespectacled, lab-coated scientist who would do periodic science segments from Muppet Labs, where the future is being made today. The muppet has no eyes, only completely transparent, lensless glasses. This makes him appear a very absent-minded intellectual. He was named after Robert Bunsen, inventor of the Bunsen Burner.
Dr. Bunsen Honeydew's name was derived from the traditional piece of lab equipment, the Bunsen burner, plus the fact that his head was shaped and colored like a honeydew melon. He was rumored to be modeled after Lew Grade, whose company ITC Entertainment produced The Muppet Show. Henson responded in a Judy Harris interview:
According to Muppet Wiki, Dr. Bunsen Honeydew is the resident scientist on The Muppet Show and host of Muppet Labs segments. In Season 1, he worked alone. In Season 2, his assistant Beaker was added to the show. He showed the audience his inventions with excitement such as the gorilla detector, exploding hats and the copying machine. Beaker is the eager assistant of Dr. Bunsen Honeydew. He made his first appearance on Muppet Labs sketches in the second season of The Muppet Show. He always communicates with his high-pitched Meep-meep-meep noises. When he tried Bunsen's inventions, he had been shrunk, cloned, deflated, turned invisible, and blown up, but he always came back for more.