There is a code in the end card the says FUN AND GAMES ARE GREAT DISTRACTIONS, BUT SMALL THINGS CAN HAVE CHAIN REACTIONS. My theory is that this references to Bill Chipher.
First of all, the cash register in the myestery shack typically displays 618(also known as Alex Hiersch's B-day), but in this episode it display's "bill" on it. This
forshadows Bill's plans to take over the world. Also, because of the portal being opened in the last episode. This could cause Bill to use the interdimensional rift to take
over. We will most liekly see more chain reactions of things happen in S2 EP14.