Because of Katsuyu's boneless body, it has the ability to divide its whole body into smaller slugs, and reunite it at will. This technique makes Katsuyu impossible to capture. All blunt physical attacks are also nullified before this technique, as no matter how violent the strike, it won't amount to more than a fruitless attempt. Any enemy who attacks her will only exhaust themselves. Katsuyu can also divide for other various purposes such as channelling its summoner's chakra into shinobi with one of the slugs on them to heal injuries.
In the Ultimate Ninja game series, Tsunade summons Katsuyu above the target, crushing whatever is beneath it and then dividing into small slugs.
This technique is an exaggerated replica of a slug's ability to self-amputate a portion of its tail to escape predators.