Cetus Square creates dynamic music and audio. You will hear ambient background music with a dynamic soundscape of water and whales. You can also use your built-in microphone for an added effect. There is also a featured "bing" button, that will...well... go "Bing!"
This app can generate endless audio content: 1) without using your network (no wifi or mobile data required) 2) with a low data profile (only ~25MB downloaded on to your device) 3) low battery usage (~%2 on modern devices).
This app does optionally use your built-in microphone. However, no data is stored, sold, or accessed other than to create the soundscapes heard. So you're safe with us.