Warren Buffet has joined the Crocs Inc. (NASDAQ: CROX) craze, at least parenthetically. Fruit of the Loom, owned by Berkshire Hathaway (NYSE:BRK.A), has joined Crocs in licensing the right to use Marvel Entertainment Inc.'s (NYSE: MVL) superheros on their products.

For Crocs, this builds on an already impressive array of tie-in arrangements, including the Time Warner (NYSE:TWX) deal Jon Ogg blogged about here last week, in which they gained the right to Looney Tunes, Hanna-Barbera and Scooby-Doo characters from the Warner Brother's closet.

Among the figures in the Marvel Universe are Spiderman, the X-Men, the Fantastic Four, and the Hulk. The Hulk will be featured in one of next summer's blockbuster-wannabes, The Incredible Hulk.

Fruit of the Loom offers character underwear featuring icons such as Batman, Scooby-Doo (they missed a bet here, not naming this line Scooby-Doo-Doo), and (appropriately enough) Nickelodeon's SpongeBob SquarePants.

See our Crocs gallery for more about the fashionable footwear.

Gallery: Crocs, from ugly to boots

The 2005 IPO of Crocs, Inc. (NASDAQ: CROX) was the "most successful ever in the footwear industry in terms of raising money," notes quantitative analyst Vahan Janjigian.

Indeed, says the editor of The Forbes Growth Investor, "The company has turned 'ugly' into a favorable feature that along with their reputation for comfort have helped boost sales by 236% in the latest quarter."

He notes that the company's tremendous success is due to the popularity of its clog-like sandals with their distinctive air holes and toe-box ventilation system. He explains, "Made from Croslite, a proprietary closed-cell resin that molds to the contours of the feet, these shoes offer an exceptionally comfortable fit."

Croslite, he points out, is lightweight, waterproof, and slip and odor resistant. The shoes became a hit with beachgoers and boaters despite their unusual look, he notes. Further, he adds, "Sales growth exploded as they gained popularity with the fashion conscious and then the mass market."

Janjigian notes, "Their unique appearance, which some call ugly, made them easily identifiable and probably added to their appeal." The shoes, he notes are now available at more than 10,000 locations in the U.S. and can be purchased in more than 8,000 locations in 80 other countries.