The Mycellium Men, individually known as Shroom, are mushroom mascot suits wearing matching overalls and a yellow scarf. The Mycellium Men band consists of a green, red, blue and pink iterations of the character. Their likeness is also used for the Musical Mycellium Men parroting plushie, which a commercial can be found for in-game. The Mycellium Men were commissioned costumes by the purchaser of the same name (most likely MCM themselves). 8 of them were ordered (2 of each color) on May 4, 1973, and picked up on November 4, 1973 (originally planned to be done by August 4, 1973). There are four Mycellium Men suits in the Retail Showroom that depict them as different sizes (notably the orange one being shorter and the green suit being taller). While being worn by the Mimic in Secret of the Mimic, the Mycellium Men emit gurgling noises voiced by Kellen Goff.
Additionally, it is mentioned in a mailbox message that Mycellium is misspelled on marketing images (it was also, weirdly enough, misspelled on the ordering sheet). Edwin replies, saying that it helps them avoid copyright issues, and that nobody will notice.
Mycellium Men has been suggested to play 10 roles. Click below to see other actors suggested for each role, and vote for who you think would play the role best.