ChuChu, as well as all the other animal friends, have the ability to share and enhance whatever ability Kirby currently has. When Kirby is paired with ChuChu, she can swallow enemies while underwater, and ChuChu has her unique ability to stick onto ceilings and "walk" on them, but she can't do the same with walls.
Similar to Laser ability from Kirby's Adventure, but continues after damaging an enemy or block. ChuChu charges up electricity in one arm, eventually releasing it. This beam, if charged fully, will bounce off hills and walls.
Many of ChuChu's abilities revolve around either Kirby and her holding hands, or spinning while looking in each other's eyes, as well as the duo constantly giggling as if content with each other's presence. This is used to guess at a romantic relationship, which became a running gag in the (non-canon) manga where she is shown to have a crush on Kirby. In addition, one of the level intros shows Gooey flirting with ChuChu and her reacting violently, and another shows ChuChu and Kine fighting over Kirby's companionship.
Unlike other animal friends, who inhale enemies or have Kirby inhale them, ChuChu reaches out her arm and if she catches an enemy, she drags it into Kirby's mouth; essentially, using ChuChu gives Kirby Gooey's tongue-lash in place of an inhale.
As seen in Sand Canyon's intro scene, ChuChu has teeth.