The first video apparently shows Henry Cavill getting his picture taken for CG-work in Justice League (or a promo), which borrows a song from Marvel's Guardians of the Galaxy, perhaps signifying it's cosmic-related.
"Heading home now...Thank you Comic Con. #JusticeLeague #SDCC2016 #BeamMeUp," Cavill posted.
The second video sees Henry Cavill donning a V For Vendetta mask hitting the Comic-Con floor and surprising an unexpected Will Smith and the cast of Suicide Squad.
"Justice League" has a November 17, 2017 release directed by Zack Snyder starring Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, J.K. Simmons as Commissioner Gordon and Willem Dafoe as an Atlantean.