Disney's famous flywheel came to life for the general public Saturday as studio executives, Imagineers and talent gathered on a SXSW stage to illustrate world building of beloved franchises as they move from TV and film to theme parks and back.

Robert Downey Jr. delighted Disney Parks fans at South by Southwest with a surprise appearance and peek behind the curtain at how he helped develop a new Stark Labs ride for Disneyland. Downey joined Marvel president Kevin Feige and Walt Disney imagineering chief creative officer Bruce Vaughn onstage at SXSW's "The Future of World-Building at Disney Panel,

Robert Downey Jr. made a surprise appearance at a featured session with Disney during South by Southwest on Saturday. Here's what we said.