Invisibility

Captain Hogthrob and Dr. Strangepork after taking "invisibility pills" aboard the Swinetrek on The Muppet Show.

Fozzie's hands after washing off Muppet Lab's "invisibility spray" in Muppets from Space.

Baby Kermit starts to turn invisible with Bunsen's "Invisi-Spray" on Muppet Babies.

Invisibility is the inability to be seen. It is often used in fiction as a plot device where objects or characters are turned invisible by means of magic or hypothetical scientific technology. Ghosts can often make themselves invisible, and invisibility is sometimes a power of superheroes. H.G. Wells's 1897 novel The Invisible Man spawned various adaptations and popularized the concept of characters turning invisible.

Ebenezer Scrooge and his ghostly guides cannot be seen by others while viewing visions of Christmases past, present and future in The Muppet Christmas Carol. As The Ghost of Christmas Past explained to Scrooge, "These are but shadows of your past. They can neither see nor hear you." Other characters have also had hallucinations and supernatural or imaginary visitors who are only visible to them and the audience.

The Muppets

• During the "Pigs in Space" sketch in episode 307 of The Muppet Show, Captain Link Hogthrob suffers from a space disease that makes him transparent.

• Dr. Strangepork invents a pill that makes pigs invisible in the "Pigs in Space" sketch in episode 324 of The Muppet Show. He and Link take the pills and play pranks on First Mate Piggy.

• Gonzo accidently turns himself invisible with a spell from his Acme Magic Book in the March 1, 1984 installment of The Muppets comic strip.

• Dr. Bunsen Honeydew shares his latest invention of invisibility spray in Muppets from Space. The spray is kept in a rubber duckie and is used by Kermit, Fozzie, Piggy, Pepe and Animal to break into the laboratories at C.O.V.N.E.T. The effect is "sadly temporary" and can also be washed off, as Fozzie learns when he washes his hands after using the bathroom during the rescue attempt.

• The Vanishing Cream Beaker Action Figure was a variant action figure from Palisades Toys that features a partially translucent Beaker―the result of one of Dr. Bunsen Honeydew's experiments gone wrong. An exclusive Invisible Beaker Action Figure was also produced with Beaker fully translucent.

• A pair of mutant superheroes known as "The Invisible Twins" appear in episode 24 of From the Balcony auditioning for X-Men III. Due to a miscommunication, one twin showed up already invisible, while the other thought they were going to start visible and turn invisible.

• Bunsen and Beaker turn a young Kermit invisible with their "Invisi-Spray" in the Muppet Babies episode "The Invisible Frog."

Sesame Street

Kermit interviews the Invisible Man on Sesame Street.

Big Bird has a sleepover with an invisible Snuffy.

• Mr. Hooper invents the "Super Duper Deluxe Invisible Raincoat" in Episode 0010. The fundamental flaw of the jacket, as revealed by a sudden shower after Mr. Hooper takes it off, is that you can't see it to put it back on.

• Lefty sells Ernie an invisible ice cream cone in a season 6 segment.

• Kermit the Frog talks with The Invisible Man (and his invisible family) in a 1977 "Sesame Street News Flash" segment.

• Slimey becomes invisible in Episode 1822.

• The Sleaze Brothers Funfair in Follow That Bird was once home to The Invisible Gorilla.

• Oscar the Grouch and Maria use "Disappear-o," a Grouch product that makes them invisible, in Episode 2935.

• Snuffy becomes invisible in a two-part story in Episode 4069 and 4070.

• Mr. Noodle's brother, Mr. Noodle walks an invisible dog in "Elmo's World: Dogs."

Fraggle Rock

The Gorg's heads turn invisible in "The Great Radish Famine."

• In the episode "The Minstrels," Cantus the Minstrel says his musical pipe was given to him by "a mysterious and invisible… a mysterious and invisible…" well, he doesn't know, it was so mysterious and invisible.

• Gorg Youth and Beauty Cream is an anti-vanishing cream, if the Gorgs don't use it, they slowly turn invisible from the head down. The Gorgs begin to turn invisible due to lack of the cream in the episode "The Great Radish Famine."

• The Invisible Garboil is a monster that flattens Fraggles in Fraggle Rock. It is accidentally released by Gobo in the episode "Gobo's Discovery."

• In the episode "Doomsday Soup," Boober's invisibility Soup makes anything it touches invisible for a short period of time.

• Wembley splits into four invisible versions of himself in the Fraggle Rock: Back to the Rock episode "Four Wembleys and a Birthday."