Short the ES and buy a call, then you're synthetically neutral.
Another option would be to identify a correlation in VIX and perhaps make a play there. Presumably a further down trend would correlate to VIX remaining high. As such there may be a play there, but then you introduce the risk of the market continuing down while VIX drops.
You could pick key players in the S&P that you think will move highly correlated with the S&P and open positions (depending if they're highly negatively correlated or positively correlated) and open positions there. There's tons of ways to do this, but they each have pros and cons such as only being a partial hedge (opening positions in specific companies) or introduce additional risk of volatility moving unexpectedly (as in the VIX play).
For example, XOM appeared to me to be a big piece of the movement at one point, so a hedge would be to short XOM -- or buy puts on XOM and other big players that are likely to drag the S&P down. I'm not suggesting to do any specific position, just throwing ideas out to hopefully get your mind thinking in different ways.