I guess one of the worst first contact messages could be a thread on a message board, with a title like:
If any alien race wanted to eradicate humans but leave all other creatures on earth
How YOU doin’?
Greetings, Earthlings. We would like you to take us to your Earth leader to whom you revere as “The Donald.”
“No, no, no… it’s ‘Blessed are the cheese-makers.’ Can’t you people get anything right? You screwed up our teleport system we set up in Egypt, the regeneration facility we put down in South America…why do we bother?”
“What goes on four legs in the morning, two legs in the afternoon, and five tentacles in the evening?”
Do you guys still have that book I left with you a few thousand years ago – you, know, my creation diary? I need to add a chapter.
*Bend over Earthlings. We’ve gotta lotta deep probing to do.
…sorry if our middle tentacles are a little stabby.*