"Phineas & Ferb" Cast's Favorite Marvel Heroes

YH is at the Disney D23 Expo in Anaheim to catch up with the human faces behind the hit cartoon series "Phineas and Ferb"! Alyson Stoner (Isabella), Vincent Martella (Phineas), Jeff "Swampy" Marsh (Major Monogram), and Dan Povenmire (Dr. Doofenshmirtz) talk about the show's Marvel crossover, including who their personal favorite Marvel superhero is, plus they reveal what would make the "best day ever" and the show's creators offer advice for perseverance in the biz! Hosted by Nikki Novak (@nikkinovak). "Phineas and Ferb: Mission Marvel" premieres August 16 at 8:00 p.m., ET/PT on Disney Channel