A few cool new features made their way to Android in Marshmallow including Doze, a battery saving feature, and Google Now On Tap. GNOT is a way to quickly find out more information about any page you are currently browsing. Long pressing your home button launches Google now on tap which gives you contextual cards.
This is a nifty feature and can help you quickly find showtimes for movies you may be browsing, info on actors or actresses from the same movie you are browsing and so forth and so on. The only real downside to this feature is that it adds an extra step to getting to your actual Google Now cards which can be frustrating when all you want to do is check the weather or a score.
Fortunately you can pretty easily turn off the feature.
-Launch Google Now On Tap by pressing and holding the home button
-Press the Google logo near the bottom of your screen
-Press the menu button (three lines) in the top left
-Click Settings then Now On Tap
-Turn it off by toggling the switch to the off position