This app was mentioned in 2 comments, with an average of 1.00 upvote
CUT-IN Manager on Android lets you add chibi sprites, which you can link to certain system messages like: phone unlocked, battery low, notifications etc.
So I've been using this cut-in app on my android phone and it's just great.Eye can get random touhou and vocaloids showing up whenever eye want...but eye dont because then a third of the time flying Miku heads and shrine maiden pop ups would get too distracting.
On an unrelated note eye tried looking up touhou phone cases for my Moto E and got decapitated Rumia instead.