Red square with the Yen symbol app, adds and other undesired stuff

Hello, i don´t know how, but there an app anoying me very much. Suddenly i started getting adds on my phone´s home and a red square with the yen symbol.

I can move that square around but cant close it. If i tap the symbol a news page opens up.
This news page doesnt display a name and hides my phone´s upper bar, the one with the time and notifications. Also, this app closes automatically if i swap between apps or tap the home button. One last thing, some times (most of the times) when I unlock my phone i get some kind of loading screen with 5 blue dots in the middle.

After the loading screen i can use my phone, but i get adds and/or the red square.

This thing is very annoying and is slowing my phone A LOT. I can´t find any strange or new apps on the app manager. Help me please.