Ding is Dang's twin brother.
He is first mentioned in Mr. DNA when Dang tells Adam and Echo why he hates his brother (he married a duck named Shirley). His first actual appearance is in Mr. Space when Mr. Tater needs a taxi (to chase Echo, Derby, Slab, and Ivy), one suddenly appears out of nowhere. Mr. Tater believes it's Dang, saying he didn't know he drove a taxi, then he introduces himself as Dang's twin brother Ding and then introduces Tater to his wife/duck, Shirley.
He possesses a same ability as Dang, but instead of saying his name to make him appear, you call for a taxi.