Koodous Antivirus for Android is a completely free app that will keep you safe from malicious apps like trojans, viruses, or abusive ads. It does this by analyzing and detecting malicious behaviors in thousands of Android applications. 

The app is an antivirus, as it looks for malicious activity, but it is also a community of experts in malware detection. They are the ones that will tell you which applications are safe to use and which are not.

So, if you want to be sure that the application you are going to use on your Android device is not going to harm your device, you should trust the experts more than the application itself.

The app uses a technique called "collective intelligence" that analyzes all the information that is collected from all the users that have installed the application.