This is a feature at the iPhone X. If you go to text someone you will probably see the monkey as an option and if you don't you can probably click on that icon that looks like a picnic table (to me) at the right of the camera icon to unlock this and other icons. When you click on the monkey icon you will have access to Aniemojis which are animals which mimic what your own face is doing. (The camera on your phone is looking at you.) You can record an audio message of an animal talking and making faces and then send it as a text message out to others.