Chloe Bennet and Clark Gregg (Agents of SHIELD) took on Hayley Atwell and James Darcy (Agent Carter) in an All-Marvel lip sync battle via the app DubSmash. All through out SDCC, these two casts went toe to toe. Atwell/Darcy even found Chloe Bennet's international pop single, but the SHIELD crew came out on top.
Step aside Captain America, this was the real Civil War.