Pokemon logo (Cubeon) showing on my boot screen

I recently installed "Pokemon Go" game in my Redmi Note 4G. The game is working fine. But I noticed something peculiar in my booting screen. It shows up just after the MIUI logo. I took a photo and did a little research and came to know that the logo is of Cubeon, a Pokemon character. I don't know why this is happening. Is there any security issues? How did the app get access to my boot menu?