The Spooky Tale of Captain Underpants Hack-a-Ween

 is an animated comedy special written by Mark Banker and starring Nat Faxon, Jay Gragnani, and Ramone Hamilton. It was released on Netflix on October 8, 2019.

Summary
"When Melvin tries to cancel Halloween, clever best friends Harold and George create their own spooky holiday -- and it's a huge success!"

- Official Netflix synopsis

Cast and Characters

 * Nat Faxon as Captain Underpants / Mr. Krupp
 * Jay Gragnani as Harold
 * Ramone Hamilton as George
 * Sean Astin as Narrator / Mr. Gigglenose
 * Dayci Brookshire as Jessica / Dressy
 * Clancy Brown as Mr. Ree
 * Jorge Diaz as Melvin / Stanley Peet / Melvin's Dad
 * Peter Hastings as Comic Narrator
 * Evan Kishiyama as Steve 'Gooch' Yamaguchi
 * David Koechner as Mr. Meaner
 * Erica Luttrell as Erica / George's Mom
 * Patty Mattson as Miss Anthrope / Harold's Mom
 * Brennan Murray as Bo Hweemuth
 * Kevin Michael Richardson as Diddlysaurus / George's Dad
 * Mindy Sterling as Melvin's Mom