A morphing outfit, sometimes called a morphing suit, is a skintight outfit (usually a leotard for Cassie and Rachel, and bike shorts and tight t-shirts for Jake and Marco) the Animorphs must wear so that their clothes are not shredded when they morph. It is the only type of clothing they can wear that will disappear along with their body into Z-space while they are morphing in another animal form. Since these outfits are not what a teenager would typically wear, the Animorphs will sometimes receive odd looks or comments on their choice of dress. Later in the series, the Animorphs learn how to morph some non-tight clothing.
In The Diversion, Marco's light blue morphing outfit is used to create blue bands so that the Animorphs, morphed as Hork-Bajir , will appear to the Yeerks to be part of the elite squadron of Blue Band Hork-Bajir.