The Tick is a superhero in a blue bug suit (which may or may not be part of his body).
He is formally introduced in The Tick #4, but appears as a mysterious flying figure in the background of earlier issues of that series.
In a running joke, Arthur is often mistaken for a rabbit because of the shape and size of his costume's antennae and because his wings are usually folded up.
His doughy physique, shy manner, lack of self-confidence, and hesitation in the face of danger are often played for comic contrast against the attitudes and tendencies of other characters (especially the Tick).
Arthur is ethnically Jewish (which is mentioned in an episode of the 1994 cartoon series), and his family wants him to leave the superhero lifestyle and return to accounting.