This is pretty classic attempt at a monopoly. Judging from the spike in the first graph, it looks like somone bought up all of the small secure containers in Jita. They then relisted them at about about 25x the price. It was like this for a few hours before somone jumped back in with a a stock of containers at a much lower price (although still 5x the previous baseline price).
It is pretty hard to monopolize the market for very long. Small secure containers are easy to produce. I am not sure how long they kept up the monopoly or how much isk they made (or lost) in doing it. I only noticed this because I was finishing up my treasure hunt containers and thought I needed a couple more. Fortunately, I had already purchased what I needed (on another character). I actually had enough to relist some on the market, but I didn’t. I wanted to hold onto my extras just in case.
If you want to sign up for the treasure hunt, I still have a few spots left. Send an ingame mail to Tas Exile as soon as possible. I relaxed the entry requirements for a couple of players that were just outside the window of character age. So if you are close and want to participate, let me know.