Google tested its AR Stickers App during the launch of Pixel 2. Now the app is available Pixel users running Android 8.1 Oreo. This app users ARCore augmented reality framework that has replaced Google’s Project Tango.
AR Stickers brings a new mode in Google Camera that allows you to drop various 3D characters into the camera scene. You can take pictures, record videos and move camera around.
Google has also launched two two branded sticker sets: Stranger Things and Star Wars for making this new feature a fun. Along with these packs, Google has several other creatures and things to use. Google will keep on adding more stickers in the future.
https://www.youtube.com/watch?v=DoS7VwKd0Ys
To use this feature, open camera app and switch to AR Stickers mode. Here select the sticker pack you want to use and move them around. You can also use multi-touch gestures to resize it, rotate it, or move vertically up and down.
Every Pixel phone will automatically download the 100 MB update to make this work. If you own Pixel phone, you just need to wait and you will see a new Mode there.