The actor -- who plays the lead in the "Shazam!" franchise -- replied to a question posed on the bird app by Lyndon Wood, who asked ... "Do you agree or not, that Pfizer is a real danger to the world?" ZL's response made no bones about how he feels, "Hardcore agree."

There's not much more context beyond that, and right away ... Twitter users started bashing the dude and labeling him as a right-winger spewing anti-vax rhetoric. This also prompted people to pull up old clips of Zach that they view as problematic -- including a Joe Rogan interview he did a few years ago, where they talked about Elliot Page and Jordan Peterson.

Of course, the jokes also started to fly in regards to WBD and how the execs there might be reacting to this news ... on its face, it comes across as a PR nightmare -- especially with "Shazam! Fury of the Gods" on the horizon and a press tour that'll undoubtedly come with it.

Welp, Zach caught wind of all the hubbub and attempted to clarify ... tweeting a link to a 2009 DOJ press release touching on a fraud case Pfizer was involved in at the time, when they agreed to pay a $2.3 billion settlement. He says this is what he was referring to.

In other words, he's now trying to make it seem like he was expressing a view against corruption in big pharma -- but, frankly, Twitter isn't really buying it ... especially amid the latest Project Veritas drop, which has been top of mind in much of conservative media.

Time will tell how this might affect things with the water tower team. One could argue WBD had a way bigger scandal on its hands with Ezra Miller ... and they ended up salvaging that pretty nicely. Their movie isn't canceled -- it's actually due to come out later this year.

Of course, it all comes down to what James Gunn and Peter Safran wanna do with "Shazam!". They're at the helm of DC now, and they've scrapped A LOT in recent months.