Just a little scared

I found this thing floating in our water tank. Though I am not superstitious, I am a little scared now because it's 2nd time we found a similar thing in water tank, previous one we didn't pay attention and thrown it in trash. But this one made me worried now.

Does anyone know what is written on it and what it is used for?

PS: We listen to the recitation of Surah Baqarah almost every other day and also read Ayat ul Kursi.