Adrenochrome
What if all the undercover agents at J6 were there just in case Pence didn't sign over the presidency. They were going to stage a protest. Rather than waste all that man power they instigated the crowd to storm the capital to cover their asses.
A plasma storm makes sense when you take into consideration all of the rock art around the world depicting the squatting man. Which is nothing more than a plasma release. They've recreated the squatting man in the lab.