Animal Partners are the companions/pets for the seven Arcobaleno that some can use as weapons or for transportation. All Arcobaleno have an Animal Partner except for Lal Mirch and the second and third Sky Arcobaleno, Aria and Uni.
Leon is a green Chameleon and the partner of the Sun Arcobaleno, Reborn. Leon represents the Sun Flame's activation ability by being able to produce special silk, create Bullets and weapons such as Tsuna's X-Gloves & Dino's Whip, and even give birth to other animals such as Enzio. Leon can also shapeshift into a gun, an umbrella, a One Ton Mallet, a rifle, or even a shield.
Falco is a white Hawk and the Animal Partner of the Rain Arcobaleno, Colonnello. Falco carries Colonnello from one place to another by flying. It also is seen sometimes carrying Colonnello's rifle in its mouth.
Oodako is the Animal Partner of the Cloud Arcobaleno, Skull. Its tentacles follow Skull's hand and finger movements. Skull uses his octopus for the majority of his attacks. Once when Skull raided Mafia Land on behalf of the Carcassa Famiglia, Reborn shot Skull's hand with a bullet, enlarging Skull's hand. Since the octopus didn't recognize the command, it froze, making Skull unable to control Oodako.
Fantasma is the Animal Partner of the Mist Arcobaleno, Viper/Mammon. Fantasma is a green frog with red eyes sitting atop Viper's head when untransformed. When transformed, Fantasma turns into a snake and bites its tail, which forms an ouroboros symbol over Viper's head. Fantasma helps Viper to stay afloat, although Viper can float without Fantasma.