This is another character from the same comic book. "Whoo-Dooit" is a variation of "whodunit", while the "doodit" part presumably is from Red Skelton, who played a character called "The Mean Widdle Kid" that kept saying, "I dood it!"
Stealing candy from a baby is supposed to sound particularly low-down, but I don't think I come across that one so much any more.
In the early days of television, bars were one of the first places you'd see them. The television on this page is supposed to be in a bar, although this isn't made really obvious - possibly because it's a comic book story which is intended for little kids.