In an August 31, 2020 Fox News interview, Trump alleged a conspiracy about opponent Joe Biden, who had been a centrist Democrat for 47 years of public service.

INGRAHAM: Who do you think is pulling Biden’s strings. Is it former Obama people?

TRUMP: People that you’ve never heard of. People that are in the dark shadows. People that are-

INGRAHAM: What does that mean? That sounds like conspiracy theory. Dark shadows, what is that?

TRUMP: People that you haven’t heard of. There are people that are on the streets. There are people that are controlling the streets. We had somebody get on a plane from a certain city this weekend and in the plane, it was almost completely loaded with thugs wearing these dark uniforms, black uniforms with gear and this and that. They’re on a plane.

INGRAHAM: Where is-

TRUMP: I’ll tell you sometime, but it’s under investigation right now. But they came from a certain city, and this person was coming to the Republican National Convention. And there were like seven people on the plane like this person. And then a lot of people were on the plane to do big damage. They were coming-

INGRAHAM: Planning for Washington.

TRUMP: Yeah, this is all happening.

INGRAHAM: But the money is coming from somewhere. How can it be tracked?

TRUMP: Money is coming from some very stupid rich people, that have no idea that if their thing ever succeeded, which it won’t, they will be thrown to the wolves like you’ve never seen before.

Trump seemed to be vaguely referencing protesters, who he also alleged had kept the city of Portland burning for “decades.” In the same interview, Trump compared killings by police to choking at golf.

NBC News – Trump claims without evidence that Biden controlled by people in ‘the dark shadows’
Politico – Trump alleges Biden controlled by people in ‘dark shadows’
CNN – The 35 most reckless lines from Donald Trump’s interview with Laura Ingraham