CuBots, also referred to as Cubots, are robotic creatures who were originally meant to appear in Super Smash Flash 2 as common enemies for Adventure Mode: The Flash Of Shadows. However, after the storyline was remade and the mode itself was scrapped, it was confirmed that they would be no longer be appearing in the game.
In the game mode's original story, CuBots were Umbra's main minions. They came in three different types, each with different attacks, although overall they shared the same role in the story. They were planned to appear as enemies in multiple levels throughout the game mode, including during the final boss fight against Umbra himself.