This is an interesting feature of Perl that's recently come up on p5p as a candidate for removal. Not obfuscated, but obscure certainly.

#!/usr/bin/env perl

use warnings;

"pointy haired boss";
"dilbert";
"dogbert";
"wally";
[download]

Outputs:

Useless use of a constant ("pointy haired boss") in void context at sc
+ratch.pl line 5.
Useless use of a constant ("dogbert") in void context at scratch.pl li
+ne 7.
Useless use of a constant ("wally") in void context at scratch.pl line
+ 8.
[download]

What? Why doesn't "dilbert" generate a warning?

Turns out that before pod became the standard for Perl documentation, people used to embed strings of nroff in Perl scripts. Any strings that begin with "di", "ds" or "ig" look enough like bits of nroff to be exempt from the void warning.