These instructions are going under the fairly safe assumption that you are rooted, as you wouldn't have messed up your animation with said app if you weren't.
The app in question puts its animation into /data/local unless you directed it to put it somewhere else.
Ok here we go;
If you don't yet have one, install a file explorer that gives you root access.
Root Browser is free and will work for what we're doing -
https://play.google.com/store/apps/...yLDEsImNvbS5qcnVtbXkucm9vdC5icm93c2VyZnJlZSJd
Open Root Browser and navigate to the location /data/local
Grant root access when it prompts you
In the location /data/local you should see a file named bootanimation.zip
Delete bootanimation.zip
Reboot and you should have the normal animation
If not I would need to know exactly what you did step by step