From Muppet Wiki

Pak-Nit, and its sister product, Pak-Nit RX, were a variety of pre-shrunken fabric produced by Compax Corporation, guaranteed to prevent shrinking and stretching during the laundry process. The company hired Jim Henson in 1965 to create three industrial films for their products.

• "Shrinkel and Stretchel," a parody of "Hansel and Gretel" featuring Taminella Grinderfall and the RX Twins.

• "Shrinkenstein," a "Frankenstein" parody featuring Big V as the Monster, Mack as PakNit RX and the Prime Minister as a Scientist.

• "Stretchelstiltzkin," a spoof of "Rumpelstiltskin" featuring King Impossible the Third, Damsel and Rumple Wrinkle Shrinkel Stretchelstiltzkin (aka PakNit RX).