Did 'Arrow' Spoil an Upcoming Episode of 'The Flash'?

There wasn't a new episode of Arrow Monday night on The CW and while fans are eager for the show [...]

There wasn't a new episode of Arrow Monday night on The CW and while fans are eager for the show to return from its brief break since it left off with a major shocker about Oliver and Felicity, it gives fans plenty of time to ponder another curious element of the "Star City Slayer" episode -- a possible spoiling of an upcoming episode of The Flash.

While there was a lot going on in "Star City Slayer," an episode which saw Team Arrow dealing with a serial killer targeting vigilantes, there was also a curious reference to the larger Arrowverse that has left fans stumped. While it's not exactly uncommon for there to be a bit of crossover between Arrow and The Flash via cameos, phone calls, and even news reports, those events aren't so common as to be ignored, either. That's why, perhaps, the issue with the "Star City Slayer" moment sticks out so much.

In the episode, Dinah Drake (Juliana Harkavy) makes a call to Central City Police's Captain Singh on The Flash in attempt to get some lead on the identity of the killer in Star City. Singh isn't able to give her much, though, commenting about an incident in which a new super-powered villain attacked, landing many CCPD officers in the hospital before being apprehended by Team Flash. While that certainly sounds like something that would happen on The Flash, here's the thing: there's nothing that's happened thus far in The Flash's fifth season that lines up with the attack. As Arrow and The Flash are generally happening at the same time, timeline-wise, it seems like Arrow may have accidentally revealed a future battle for Team Flash.

But, how far in the future are we talking? That's not exactly clear. When The Flash returns with a new episode next week, it will be with "King Shark vs. Gorilla Grodd", two characters that don't fit Sing's description of the metahuman threat being a new one -- both King Shark and Gorilla Grodd have appeared on The Flash before. It also seems to eliminate the March 12 episode, "Failure is an Orphan" which, based on its official synopsis, appears to be a Cicada-centered episode and Cicada isn't a new threat either.

Fans will just have to keep watching The Flash to find out what Singh was talking about when Arrow called.

Arrow airs Mondays at 8/7c and The Flash airs Tuesdays at 8/7c on The CW.