How do you write in the sky on angry birds?

I was recently going on a road trip, and let my cousin play with my iPad. Now, my brother brought it to my attention that on level 8-3 in regular angry birds (danger above) the words "Ethan" was written in the sky with stones. I'm so confused? Can anyone please tell me how to do this and get rid of it at least? And it's even like, part of the level. Because you can destroy it with a bird, but it just comes right back when you restart. Also, I have a screen shot of it, if anyone would like to see. Please help!