This morning we got the first full trailer for the upcoming Incredibles sequel, which included the first real look at the story's villain. After the final title card in the trailer, we are introduced to a character called the Screenslaver. We got a glimpse of him in the new poster released yesterday and the trailer gives us a bit more information. While there's a lot we don't know, the trailer does seem to tell us a bit about the Screenslaver's power set. He appears to focus on hypnotism as his primary ability.
The last few seconds of the new trailer introduces the Screenslaver as he interrupts a television program to announce, I'm assuming, whatever his evil plan will be in the movie. We then get some flickering lights and a shot of what could be a security team looking at banks of monitors. What's of interest here is that all the guys in suits are staring straight ahead and they all have a glassy-eyed look, like they're not actually looking at anything. Also, Elastigirl appears to be shielding her eyes in the back of the shot, possibly trying to avoid being affected by whatever is happening.
This, combined with the character's name, leads me to believe we're dealing with a character who can hypnotize people, probably with a goal of controlling them and getting them to do things for him in order to carry out his scheme. The name "slaver" certainly implies he'll be making slaves out of people.
Of course, the other part of his name is probably also relevant. We see these security guards looking at monitors as well as a crowd of people watching the Screenslaver on televisions in a store window. Another shot in the trailer shows us what they're looking at, a sort of test pattern with a swirl in it, which is probably the image that does the actual hypnotizing of the populace. It seems anybody looking at a TV at the wrong time could be affected.
If screens are necessary for the Screenslaver to hypnotize people then it's possible that he's not even a Super in the Incredibles sense. Like Syndrome in the first Incredibles movie, who used technology to give himself powers, it's possible that the Screenslaver also uses tech to hypnotize people. We can't tell from what we see here whether or not he has a natural hypnotizing ability that he could use if he were standing in front of somebody. The answer to that question will probably be quite relevant in the film.
There's still a lot we don't know about the Screenslaver, like what it is he (or she, it's not actually clear) plans on doing with this ability, if there's anything else he can do, or who it actually is under the mask. We'll learn more about what the Parr family is up against when Incredibles 2 hits this June.