This Tweet was clearly meant to intimidate Comey into remaining silent about what was said when he had dinner at the WH.
Comey will still be called to testify before Congress, and now as a private citizen, he becomes a witness.
Surely as a witness, he will be asked about what was said at that dinner, and in any subsequent contacts he had with the POTUS.
I believe they have a term for that when someone tries to intimidate a witness into remaining silent.
Oh yeah. It's called 'intimidating a witness.'
Next time Comey testifies before Congress, don't be surprised if you see his brother Shemus brought in from Ireland, sitting in the hearing room.
"I never had dinner at the White House.
I got my own food, Senator."