PROBLEM
Do you see the same things I see? The glimpses of the flag hidden away? http://2018shell1.picoctf.com:29568 (link)
HINT
What part of the website could tell you where the creator doesn't want you to look?
SOLUTION
No it has nothing to do with the show 😄
Name of the challenge gives you an idea of checking the robot.txt. So visit http://2018shell1.picoctf.com:29568/robots.txt and you'll see that there is a url that is been Diallow. Visiting that (http://2018shell1.picoctf.com:29568//74efc.html) URL will lead to the flag.
FLAG - picoCTF{th3_w0rld_1s_4_danger0us_pl4c3_3lli0t_74efc}