B.W.'s big brother

The Big Brother Mega-Transforbalizer is D.W.'s version of Arthur for her story in the episode, "I'd Rather Read It Myself."

After he and Bust-Rantor stole Agent B.W.'s snowball, the agent set out to stop them. She planned to sneak up on them at their hideout, but they spotted her. The two villains began chasing her until they got caught in a lake of 1 million octopuses.

Later, B.W. fell for their "ol' phoney-baloney snowball trick" and got close enough for them to capture her, believing he was Crazy Bus. Spanky soon came to her rescue and hit the button on BBMT's chest, making him turn into a cage, with the two villains trapped inside.

Abilities
His powers include shapeshifting and any additional powers that come from his new forms (ex: flying, super strength). Considering how Bust-Rantor was disguised as Pickles the clown in the Crazy Bus form, BBMT may have some limited ability to share his transforming powers.