If you are trying to beat the baby Chauncey then, here is your answer. Ok first, go to the rocking horse in the back of the room. Then, start sucking the rocking horse so that it begins to rock back and forth. Chauncey will appear over top of the horse and ask if you want to play with him. As soon as he starts attacking, suck up the ball so that it gets stuck on the vacuum, then, keep sucking until you are aiming at Chauncey, finally, stop the sucking and switch to blowing, the ball should shoot at Chauncey, after that he will turn Luigi little. Avoid the rocking horses and when he starts throwing balls at you. When one hits the back of the crib and bounces to the front, suck it like you did when you were normal size and shoot it at him, if it hits him then aim your vacuum up a little bit and when his heart appears, start sucking him in, if you don't get him the first time try again, before he starts throwing the rocking horses, he will cry and start pounding the ground with his stomach, avoid this and repeat the above. When you have finished him off, you will be transported back to the lab.