Grezar

Super Cybeast, known as Super Cyber Beast (超電脳獣) in Japan, is the combination of the two Cybeasts Gregar and Falzar exclusive to the Mega Man Battle Network series anime and manga.

Anime
After the battle between Gregar and Falzar in episode 24 of Rockman.EXE Beast, Lord Wily of Beyondard uses Trill to combine them into one, creating the Super Cybeast and using it as his vessel. With his new body, Wily attacks both worlds. Super Cybeast and Wily were defeated by MegaMan in episode 25, and the portal between the two worlds is closed. In Rockman.EXE Beast+, the Professor tries to revive the Super Cybeast again and it is defeated again for now.

Manga
When Gregar and Falzar awakened in the MegaMan NT Warrior manga, they combined into one Cybeast, Super Cybeast when they confront each other. With its new powers, the creature is able to appear in the real world and begins to absorb the Earth, growing to insane sizes. MegaMan and Bass fight against it to save the world.

Trivia

 * Fans tend refer to it as Grezar, which is a mix of the two English names.