Beat

Beat (ビート) is a robotic bird built by Dr. Cossack for Mega Man as a gift for saving his daughter Kalinka. He doesn't like carrying weighty objects, but he carries Mega Man anyway. In Mega Man 5, Mega Man 6 and Mega Man IV he attacks enemies that appear in the path (he can't attack bosses in Mega Man 6), in Mega Man 7 he can save Mega Man from pits, in Mega Man 8 he helps out in the sections Mega Man uses the Rush Jet, and in Mega Man and Bass he creates a shield to protect Mega Man, and he also protects Proto Man and Duo in the arcade games Mega Man: The Power Battle and Mega Man 2: The Power Fighters. In the game Marvel vs. Capcom: Clash of Super Heroes, Beat takes the form of a small plane in one of the special attacks used by Mega Man and Roll. He also combines with Rush, Eddie, and Mega Man/Roll in MvC and Mvc2 to create a huge version of Mega Man that shoots a wide beam across the entire screen with energy duplicates of Beat, Rush, and Eddie.

In the MegaMan Battle Network series, Beat's counterpart is a Navi Customizer program that appear once per battle in multiplayer NetBattles to take one the opponent's Mega/Giga chips to the player use.

Mega Man and Bass CD data
A bird-type robot that Dr. Cossack has presented to Megaman. He can grab and carry Megaman. "Go on a diet, Megaman." Good point: Speed & power Bad point: Wanderlust Like: Flying Dislike: Heavy cargo 

Trivia

 * His saying ("Go on a diet, Megaman.") and his dislike (heavy cargo) may have something to do with his funny expression in Mega Man 7 when he rescues Mega Man from a pit but he rides him for too long.