Yes, this warning was actually issued by the USGS.
The US Geological Survey is warning residents not to try and roast marshmallows over the erupting volcano.
They responded to one Twitter user who asked, “Is it safe to roast marshmallows over volcanic vents? Assuming you had a long enough stick, that is? Or would the resulting marshmallows be poisonous?”
They tweeted back: “Erm, We’re going to have to say no, that’s not safe. (Please don’t try!)”
I mean...really? Do you really have to ask that question, it's a VOLCANO?!