the October Surprise would have to be something that actually flips the odds on the election result.
it won't be enough for the DS to simply create chaos that may or may not make POTUS look bad. It has to actually flip the odds.
Use your imagination as to what things would reverse the current situation, which increasingly looks like one in which DJT wins 90% or more of electoral votes.
Scenarios like Yellowstone going off, San Andreas EQ, and asteroid impact don't do anything to make a Dem candidate look better to voters than DJT.
The October surprise must be something else. Imagine you were the sinister head of the DNC and you had unlimited funds plus blackmailed judges, lawmakers, SES employees, and military officers. What schemes could you cook up?