Tango is a supporting character from the classic Mega Man series.
A cute robotic cat, and one of Mega Man's more useful allies, Tango debuted in Mega Man V. Tango can change himself into a buzzsaw and dive into enemies. Tango returned in Rockman & Forte: Challenger From The Future for the WonderSwan and was featured in Mega Man 10. Despite his small number of appearances, he has a large fanbase.
In Mega Man V, Tango rolls toward the screen to attack enemies. Tango vanishes when the energy is depleted, when falling into a pit, or when the player leaves the room where Tango was used. He functions much the same way in Challenger From The Future.
Tango is also a Navi Customizer program in the MegaMan Battle Network series, shaped like a green cat with a bandage roll on its head. When equipped, Tango appears once during each multiplayer NetBattle to heal the player and give them a barrier. He is available from MegaMan Battle Network 3 to 6. While there is no official artwork of the Tango program from Battle Network, there is concept art.
The Tango program also appears in Battle Memory from Rockman ×over.