Season 4, Episode 13
"Bright Lights, Dean City"
Context: Dean Venture, the younger of "Super Scientist" Thaddeus Venture's two sons, has taken a summer internship position in the labs of Professor Incredible (a parody of Marvel's "Mr. Fantastic"). Unbeknownst to the naïve Dean, Professor Incredible has turned evil, partnering with the criminals Phantom Limb and Baron Ünderbheit to form "The Revenge Society." Hoping to increase their numbers, they stage an audition of sorts for would-be super-criminals.
Exegesis: This reference is a little unique, insofar as Mormons are not ever explicitly mentioned. But two things make clear the Mormons are the intended target of the farce: One, the reference to polygamy. It's hard to have a reference to polygamy without Mormons coming up these days. The second is the reference to "Magic Underwear". This is a popular meme, because it sounds so ridiculous, and is repeated occasionally even by otherwise well-meaning people who are unaware of how offensive that characterization is to Mormons.
Obviously Mormons do not wear magic underwear. Using the word "magic" to explain any aspect of religion is likely going to be an offensive association for believing members of that religion. (Except for Wiccans, I suppose.) We believe in miracles, not magic. That may be a distinction that that many non-believers don't recognize, but it's crucial to believers. When something a religion believes to be divine is called "magic" the implication is that the believers are rubes, and that the apparent power is an illusion or a trick. It may well be pointless to argue about the power of God and its effects with someone who denies that power even exists. Atheists (although they are not the only ones who make snide and derisive comments regarding Mormon beliefs) tend to approach religion from a position of great condescension, since they almost by definition consider themselves to be more intelligent or reasonable than virtually all religious persons. Calling Mormon underwear "magic" simply reeks of that kind of supercilious and patronizing attitude. In the context of this clip, the "magic underwear" is likely mentioned because the scene is, after all, a super-villain audition, and magic is very real in the realm of comic books and superheroes/supervillainy.
Also, "underwear" is a funny word. Okay, that's debatable, but most things that are of an intimate or private nature, like most bodily functions, tend to be mined repeatedly for comedy. It's puerile and it's immature, but this kind of low humour is also frequently hilarious in the right hands. The fact that this time it was coupled with a backhanded insult to members of the Church of Jesus Christ of Latter-day Saints is too bad, but is also to be expected when people who are not of our faith encounter aspects of it they do not understand.
This may not be an ideal forum in which to correct this particular misconception, and the people who call our underwear "magic" are not likely to be very anxious to have their misconceptions corrected. Essentially, the garment worn by faithful adult Mormons who have been through the temple is a symbol of our commitment and the covenants we've made - "an outward expression of an inward commitment". I've always liked the way that apostle Boyd K. Packer explained the temple garment - he compared it to the robes of an ordained priest, except that we wear our symbolic "robes" all the time. At any rate, the garments are considered sacred by Mormons, and the cynical denigration of anything that any religion holds sacred is never terribly amusing to me. As the Prophet Joseph Smith wrote, "We claim the privilege of worshiping Almighty God according to the dictates of our own conscience, and allow all men the same privilege, let them worship how, where, or what they may."