Google announced a new ad format for Google AdSense display ad units named magazine ads.
So instead of the display ad looking like a banner ad with animation or various popping colors, magazine ads are very minimalistic.
Google said they "designed with print magazine ads in mind, putting a big emphasis on space and typography and displaying a new look distinctive from our regular text ads."
Here is a picture of the ad unit:
You can opt out of these ads, if you want. So just be on the look out and watch your earnings closely.