Fat suits are an elaborate accessory to several costume ideas. You can buy or rent a fat suit at a costume store, or make one yourself using a unitard and foam latex pillows. Once you have the fat suit, you can design a variety of costumes around it for your next costume party or event.
Sumo wrestlers are popular fat suit costumes. Other than the fat suit, the costume requires few components. You need a large pair of briefs to wear as shorts, and possibly a black hair wig done in a sumo hairstyle. You can use your own hair if it is long enough. The fat suit will likely cause you to walk like a sumo wrestler, which further enhances your costume. This costume is especially funny on petite or skinny people.
A walrus costume is made better with the use of a fat suit. Walruses are notoriously covered in blubber, and are not a popular costume idea for Halloween or costume parties, so you will stand out wearing this costume. Wrap grey fabric around the fat suit and get some long tusks to attach to your face. You can make the tusks out of household items like tennis ball tubes or toilet paper rolls; just cover them with white fabric. Other similar costume ideas are an elephant or a whale.
Fat Albert was a popular TV cartoon character was created by Bill Cosby in the 1960s, and became a cultural icon over the years with his famous phrase, "Hey Hey Hey, it's Fat Albert!" The cartoon ran on TV from the early 1970s until the mid-1980s. If you are going to a costume party with a group, dress as Fat Alberta large red sweater and jeans over your fat suit--and have the other people in your group dress as other Fat Albert characters: Mushmouth, Dumb Donald, Weird Harold, Bucky or any of the others.
Sherman Klump/Fat Bastard
Other iconic heavyset movie characters provide additional fat suit costume options. Fat Bastard from Mike Myer's "Austin Powers" movies, and Eddie Murphy's "Nutty Professor" character, Sherman Klump, are possibilities.