There hasn't been a proper crossover between Marvel and DC Comics since 2003-2004's JLA/Avengers, but the rival publishers were able to find common ground this week -- on social media, at least, thanks to the #MakeMineMilkshake hashtag that aims to stand up to online trolls.

DC Comics made a rare and overt reference to Marvel on its Twitter account on Tuesday, sharing a group photo of its female employees along with the words, "Cheers @Marvel ladies! #MakeMineMilkshake." Marvel quickly responded with an image of a milkshake with two straws, encouraging the solidarity between the two companies.

Cheers @Marvel ladies! #MakeMineMilkshake pic.twitter.com/3Xky93iFSN— DC (@DCComics) August 1, 2017

The #MakeMineMilkshake hashtag originated after Marvel editor Heather Antos (whose credits include Deadpool and the Star Wars titles), shared a photo on Friday, July 28 via Twitter of herself and six co-workers enjoying milkshakes, with the caption, "It's the Marvel milkshake crew! #FabulousFlo." The hashtag was in reference to longtime Marvel employee Flo Steinberg, who passed away five days earlier.

The image of co-workers bonding over dairy-based deserts in tribute to a comics legend attracted negative attention from the corner of the online superhero comics fanbase regularly threatened by increased diversity in the industry, apparently disturbed by the image of seven women working at a major comics publisher. Responses to the image ranged from describing Antos and her co-workers as "the creepiest collection of stereotypical SJWs" to somehow linking the photo to Marvel's recent downturn in sales.

In a subsequent tweet, Antos wrote, "How dare I post a picture of my friends on the internet without expecting to be bullied, insulted, harrassed, and targeted." After awareness spread of the responses Antos and her co-workers received, the hashtag #MakeMineMilkshake began to proliferate on Sunday, with fans and comics professionals sharing images of themselves drinking milkshakes (or similar beverages) and the message that harassment will not be tolerated.

Marvel acknowledged the efforts that same day, tweeting from its official account with an image from Kieron Gillen & Jamie McKelvie's Young Avengers run simply accompanied by the #MakeMineMilkshake hashtag. On Monday, Antos posted a photo of more than two dozen Marvel employees with milkshakes, dubbing it the "Marvel Milkshake Crew (part deux!)."

#MakeMineMilkshake pic.twitter.com/s6o7ejVRWj— Marvel Entertainment (@Marvel) July 31, 2017

Archie Comics has also showed support, responding to Marvel and DC on Twitter with an image of a milkshake with three straws (both representing the three publishers, and a common image to Archie fans evoking Archie, Betty and Veronica sharing a shake).

While Marvel and DC Comics crossovers were commonplace in the '90s, interaction between the two companies has been rare for the last 13 year or so. The last time Marvel and DC notably acknowledged each other on social media was in April 2015, as DC Comics editorial prepared to leave its headquarters in New York City for its new home of Burbank, California. Marvel, based in NYC since its inception, responded to DC via Twitter with a gif of a tearful Rocket from Guardians of the Galaxy, saying goodbye as its rival publisher moved coasts.