You and your friends are having camping in the forest, there's some warning to not enter but you guys are too stubborn to listen

You and your friends found some notes, a old notes in the trees, says "leave now" you guys have death wish?" "No eyes but watching" and more, your friends thought it's just a joke while you're slightly worried

After your friends finding the notes, they slowly got missing.. how? Who take them? You and your best friend is the only one left