Did you know that in the Android SDK there is a function called 'isUserAMonkey' and another called 'isUserAGoat'?
https://developer.android.com/reference/android/app/ActivityManager.html#isUserAMonkey()
https://developer.android.com/reference/android/os/UserManager.html#isUserAGoat()
What are they? What do they do? With this app you can test them and learn a bit about their purpose.
As usual, this app is extremely small (less than a standard picture), totally free, contains no ads, has no permissions, and their sole purpose it to act as an interactive explanation of two strange easter eggs in the Android SDK.