The minimum evidence I would accept would be a widespread TV news reports quoting several sources over a number of months backed by a multi-government investiga

The minimum evidence I would accept would be a widespread TV news reports quoting several sources over a number of months backed by a multi-government investigation. Of course if it turned up on one of my camping trips to introduce itself I'd believe, but would just keep it to myself. I could imagine meeting it again at a public function and we exchange knowing nods; 'Dude', etc. It's very likely to need a space suit and couldn't drink beer.