Problem: Do you see the same things I see? The glimpses of the flag hidden away? http://2018shell.picoctf.com:10157 (link)
Solution:
Go to the site and there’s nothing there.
There’s nothing in the source code, either.
BUT, The title is a hint. Let’s visit the robots.txt at http://2018shell.picoctf.com:10157/robots.txt
Then we see Disallow: /143ce.html. After going there we get the flag.
Flag: picoCTF{th3_w0rld_1s_4_danger0us_pl4c3_3lli0t_143ce}