The casts of "Agents of S.H.I.E.L.D. and "Agent Carter" may have appeared friendly at the joint Marvel TV panel at San Diego Comic-Con but off stage a (Dubsmash) war was brewing.

"S.H.I.E.L.D." stars Chloe Bennet and Clark Gregg fired the first shots with their lip sync version of "It Takes Two" by Rob Base and DJ EZ Rock. They then followed it up with Rihanna's "B---h Better Have My Money."

The co-stars really threw down the gauntlet when they recruited the rest of their "S.H.I.E.L.D." cast mates for an epic rendition of Queen's "We Are The Champions," which ended with Gregg dressed up like Hayley Atwell's character Peggy Carter.

By that time, "Agent Carter" co-stars Atwell and James D'Arcy had seen enough and they faced off to settle the "Bad Blood."

Still hurt by Gregg's "bastardization" of her beloved character, Peggy, Atwell chewed on a piece of bread and sobbed to the sounds of ABBA's "The Winner Takes It All."

Atwell and D'Arcy fired the final shot in the Marvel TV battle, once again choosing a Taylor Swift song but not the original version. D'Arcy makes a beautiful screaming sheep.

BONUS: Bennet and her "S.H.I.E.L.D." co-star Brett Dalton indulged the fans who want to see their characters Skye and Ward end up together. These stars "really like" those Skyeward shippers.

The Dubsmash app went live last November and has become a favorite for celebrities looking to channel their favorite singers or quote the best movie lines.

"Agents of S.H.I.E.L.D." will return for its third season on Tuesday, Sept. 29 at 8 p.m. on ABC. "Agent Carter" will be back for its second season in 2016.