Two of the makers of Schaffrillas Productions, a popular YouTube channel, died in a car crash in Pennsylvania's Lehigh County on Sunday.

Christopher Schaffer, 25, and Patrick Phyrillas, 22, were pronounced dead at the crash site. They both died from blunt force head injuries and were passengers in the car, according to a Lehigh County Coroner's Office press release.

James Phyrillas — Patrick's 25-year-old brother — was in stable condition in the hospital on Tuesday, Brian Downs, a spokesperson for the Lehigh Valley Health Network, told NPR in an email.

Police said their car was struck by a commercial tractor-trailer while crossing an intersection. Police confirmed to NPR that there is no traffic signal at the intersection where the crash occurred.

The cause of the crash is still under investigation by local officials. Police say they aren't aware of the other driver's condition as of Tuesday.

A Twitter account speaking on behalf of the Schaffrillas editing team shared the news of the crash on social media and said all videos are on hold.

Fans expressed disbelief and condolences and wished James a fast recovery, largely under the hashtag #PrayForSchaffrillas. Schaffer's partner started a GoFundMe to cover the family's funeral expenses.

Schaffrillas Productions got its name by mashing up the last names of James Phyrillas and Chris Schaffer. The channel began in 2015 by making videos known as "YouTube Poop," or video mashups that remix existing media for comedic or satirical effect.

Now, the channel specializes in analysis videos and animations. The channel has more than 1.6 million subscribers.

A fan favorite is their Shrek 2 analysis video, which has been shared by fans reflecting on the channel and its impact.