How many movies have Alan Burnett and Doug Langdale collaborated on?

They have worked on 4 movies together! Their first movie together was Scooby-Doo! Legend of the Phantosaur (2011) while their highest rated movie together was Scooby-Doo! Shaggy's Showdown (2017). They have not worked together since Scooby-Doo! Shaggy's Showdown (2017). They are most known for their comedy films together.