Throughout the history of science fiction films, there has been an underlying fear that one day aliens will come to Earth and attack - and frequently, those aliens have been from the planet Mars. Perhaps because Mars is relatively close to Earth, as far as planets go, from Mars Attacks to Mars Needs Moms to Santa Claus Conquers the Martians, it's almost as though entertainment has been warning us for years about creatures from the red planet.

Supergirl has taken a somewhat different look at martians, however. On the show there are two kinds of martians, green martians and white martians. Main character J'onn J'onzz is a green martian, and a kindly father figure to Supergirl and her friends. And while the white martians committed genocide against the green martians, white martian M'gann M'orzz has proven herself to be an ally to J'onn.

However, in the extended trailer for the next episode of Supergirl (which you can watch above), it would appear that M'gann's past is catching up with her. The episode, titled  'The Martian Chronicles', shows a white martian on Earth who is not as friendly and kind as M'gann is. When it comes after her, to punish her for trying to help the green martians in the past, J'onn and Supergirl decide to protect her. And it doing so, it would appear that the entire DEO is put in danger.

Martians have the ability to disguise themselves as anyone and Supergirl's two recurring martians look human, most of the time. J'onn is generally disguised as Hank Henshaw, the former leader of the DEO, though a couple of times he pretended to be Kara/Supergirl to fool her old boss Cat Grant, during Supergirl season 1. It looks like that ability might endanger the DEO team in 'The Martian Chronicles', as a white martian gets loose at the DEO and can pretend to be anyone inside the organization. That includes all of the main characters, plus dozens and dozens of DEO employees whom the audience may not have met before.

In the episode's trailer, there are a few moments that might give away who the white martian disguises itself as. There's one shot where Alex draws a gun, but it is not clear who she is aiming at. Another show shows Winn getting ahold of something that looks like a flame thrower and using it to keep a group of people back. Now, in both cases they could be defending themselves against the attacker - or, they could be the white martian in disguise. It's pretty hard to tell from 'The Martian Chronicles' trailer alone.

This Supergirl episode might also provide a little closure for J'onn. His entire family was killed by white martians and he attacked M'gann when he thought she was like all the other white martians; so clearly, he still needs some form of revenge or retribution against his family's killers. If he gets to take down this white martian and save the friends who are like family to him now, it might help J'onn to further heal.

NEXT: Metallo Returns in Upcoming Supergirl Episode

Supergirl continues with 'The Martian Chronicles' on Monday, February 6 at 8 p.m. on The CW

Source: The CW