What will be the democrat surprise?

OK. So, Biden is locked away in his basement and will not make a public appearance until he is forced out on Thursday to face Trump.  Evidently, the evidence of Joe and Hunter's crimes is overwhelming, and Joe is unable to deny or defend his corruption.  Not a good situation for the last 2 weeks of a Presidential campaign.  So, that means that the only thing left for the democrats is to attack with some contrived charge against Trump.  But, the problem with that is that the democrats have been doing that for the past 3+ years and have pretty much used up all of the charges that they can fake.  Like they tried "Russian collusion" again, and it gets shrugged off.  It is too obvious a lie to be used anymore.  So, the question is can you think up a fake charge that the democrats could use that would have some bite to it?  What could it be?  Something that would get Trump personally right before the debate.