How many movies have Cassandra Peterson and Frank Welker acted in together?

They have worked on 3 movies together! Their first movie together was LEGO Scooby-Doo! Haunted Hollywood (2016) while their highest rated movie together was Happy Halloween, Scooby-Doo! (2020). They have not worked together since Happy Halloween, Scooby-Doo! (2020). They are most known for their comedy films together.