Chuck is all about speed. He thinks fast, talks fast and moves even faster. He zips around the island in a yellow flash. His frenetic energy has him jumping from one thought to the next without waiting for anyone else to catch up. Chuck lacks any kind of filtering mechanism - you never know what will come out, and for that matter, neither does he.
He is the least common figure in the theme thus far.
In the film, Chuck was voiced by Josh Gad who also voiced Olaf in Frozen.