Trump is claiming that Obama personally directed people to wiretap Trump's offices and homes.
He's making baseless claims via Twitter.
[Edit: Of course, Obama's offices have immediately denied any of this, and many intelligence officials have come out saying it is ridiculous.]
I've seen this time and time again: Trump and his supporters yell louder and more obnoxiously that their enemies (whichever they are referring to at the time, there are many, real and imagined) are doing something bad. Only...it always seems to turn out that Trump and his team are doing it worse, or more, or more illegally.
So, Trump claims that the media is making stories up without claiming sources. You've heard this yourself many times from Trump: "Fake news. The media is making things up without sources...it's fake news, and it's illegal. They're the enemy of the people."
I don't believe that the mainstream media actually fabricates stories out of wholecloth and hides behind anonymity. I might not know, but I don't believe it.
Trump, on the other hand, does it in plain sight. His outright lies and fabrications are legion. They're *everywhere*. Even his buddy Putin has backed away from this train wreck of a presidency.
He's making wacky stuff up, and his followers are swallowing it hook, line and sinker.
This article discusses a few of the reasons behind this. Partly "Illusion of truth effect", (which explains Trump's craving for and need of the media), and partly "inability to self assess", Trump and his supporters simply can't see the flaws and problems with their reasoning.