What do you do if one of your stocks spikes up?

One of the stocks that I hold is Moneysupermarket, a UK company that websites revolving around price-comparison and personal finance, etc. Today, the stock spiked 12% an hour after opening. There doesn't seem to be any reasons behind it apart from a video that one of the important people in the, Martin Lewis, the Money Saving Expert. UK also reported the latest inflation figures so it could be that the thesis is more people will use Moneysupermarket's price comparison tools. Yahoo Finance page for stock: https://finance.yahoo.com/quote/MONY.L?p=MONY.L&.tsrc=fin-srch

I personally think that the stock has good fundamentals, barely any debt, pays a good dividend and has good growth expectations, good profit margins, etc. However, such a spike I find suspicious given the bearish trend and the macroenvironment right now in the UL. My natural response was to sell out 100% and get a nice 15% profit, now waiting for an eventual drop to reenter.

My question is how would you act in this situation? Half the time, such a sudden spike is followed by a drop, the other half it remains or starts an upward trend (and naturally, if I sell, it typically keeps going up, but if I hold, it drops. Classic!). What do you consider when making the decision?