Bob is one of the "Famous Balloon Brothers". He is in the main area 15. He gives out the quest: "Three Luftballoons" in which you must find 3 balloons and show them to him.
"Helloaphant! I am Bob, one of the famous balloon brothers. I am the most famous one, of course. I LOVE BALLOONS. I would love to see 3 BALLOONS if you find them, let me know!"
"Hey did you find 3 balloons yet? That's not too many, keep searching around! You'll find them!"
"I love balloons. Do you love balloons as much as I do?"