Words cannot describe the bizarre, jaw-dropping nature of a long-lost promo for Nirvana's third studio album, 'In Utero' just surfaced. The would-be commercial for 'In Utero' features "pregnant" Nirvana members Kurt Cobain, Krist Novoselic and Dave Grohl taking a birthing class taught by comedian Bobcat Goldthwait in drag. Yes, you read that correctly.

At this point in Nirvana's career, they were the biggest band in the world. On the heels of their sophomore milestone, 'Nevermind,' the seminal grunge act needed to make a massive splash with their following full-length, but until now, we had no idea that splash was created by Cobain, Novoselic and Grohl's water breaking simultaneously.

Set in a science classroom, grocery store chickens are fitted with plaid diapers to educate the band on how to care for a human baby. With the support of Goldthwait, Nirvana are practicing their breathing patterns on the school floor when suddenly, the unthinkable happens. Not only do the Nirvana members give birth in that very classroom, but a oddly high number of babies are launched at Goldthwait via the musicians' nether regions.

This lost piece of gold has just now surfaced to help promote the 20th anniversary deluxe reissue of 'In Utero,' which will see a September 2013 release date.

Check out the rare Nirvana footage in the video above!