You would need to short an insane amount of stock for that to be profitable.

Options. Also there's potentially SEC stuff which happens to you if you do this, although it's less clear if you're not a professional or licensed, and don't solicit others.

And then there is the whole thing where if you are trying to manipulate the stock you maybe don't care who the car belongs to.

Yes, as rdl said, buy out of the money PUTS. You'll 5-10x your money. There are multiple ways to take a short position ;)

Anyway, this was in jest. But I also wanted to bring attention to the fact that TSLA is in unique position to be sabotaged for gain, more so than just about any other public company.