bad matchup. kabuto summons manda II. 2nd mizukage summons his clam. manda II crushes it under its big belly. kabuto jumps on top of him and casts sound genjutsu once thats done. and once that is done, he opens up a fissure using muki tensei and crushes him.
actually base kabuto is probably more than strong enough with his own liquid mode, and orochimaru jutsus. add in jirobos doton and you have yourself a kabuto win