It started simply enough: Pratt posted a picture on Twitter of himself with Macklemore and "The Lego Movie" writer Chris Miller celebrating the Seattle Seahawks comeback victory over the Green Bay Packers on Sunday.
That got Captain America's attention on Monday.
"Well, well, well @prattprattpratt, looks like our teams are going into battle," wrote Evans, who apparently is a New England Patriots fan. "For the next 2 weeks, you are not my friend, you are my enemy."
"We both know there's only one Captain America and his name is Russell Wilson," Pratt taunted, name-checking the Seahawks QB.
"them's fightin words," Evans replied. "Stakes? #whatisaseahawkanyway #somethingtombradyhunts."
Pratt was quick with what he wanted: "OK. Seahawks win you fly yourself to Seattle, visit @seattlechildren hospital as Captain America, waving the 12th man flag."
The "12th Man," for the uninitiated, refers to Seahawks fans, who are the loudest in the NFL. Seattle Children's Hospital is less than seven miles north of CenturyLink Field, where the 'Hawks play. (Sorry to go all basic on ya -- we're interpreting this for folks who are more about fandom than football! Take notes if you're truly worried about having something to say on Super Bowl Sunday.)
Evans accepted. "And when the Patriots humiliate your seachickens, I expect Star-Lord to arrive at @chris_haven in a Brady jersey."
That would be Patriots QB Tom Brady, a.k.a. Mr. Gisele Bundchen. Christopher's Haven, located in Boston, about an hour's drive northeast from the Patriots' home field, is a place where kids and their families can stay while they battle cancer. Star-Lord is the alter-ego of Peter Quill, the character Pratt played in -- OK, enough.
FOR THE RECORD
Jan. 21, 5:01 p.m.: An earlier version of this article incorrectly had "Guardians of the Galaxy" character Peter Quill's last name as Quinn. Hey, we didn't profess to be explaining comic books.
"Humiliate my Seahawks?" Pratt scoffed on Wednesday, the day after the world learned New England had under-inflated 11 of the 12 balls it used in Sunday's blowout victory over the Indianapolis Colts. (That's a bad thing.) "Maybe talk to Brady about deflating your expectations. BOOM! (legion of) You're on sucka."
The Legion of Boom, of course, refers to the Seahawks' secondary, notably featuring Richard Sherman -- and if you didn't know that already, well, you were probably on Chrissy Teigen's side in this other NFL-related celebrity Twitter tangle.
This story in a nutshell? Chris Pratt likes the Seahawks. Chris Evans likes the Patriots. Whoever's team loses will have to go do something cool for some sick kids.
And yes, we've been talking about football.