It would be hard to come up with a language feature that Perl invented itself.
Perl's "regexes" are quantitatively more powerful than most regex dialects, rather than just syntactic sugar run amok. I suppose if you want to be really fussy about it, all languages build on work done by Church and Turing (and you can probably go back to Peano and even Euclid if you want), but that's starting to get a little bit ridiculous.
Hmm... Church numerals in Perl? Sounds like a decent obfu gimmick.
Yours in pedantry,
F o x t r o t U n i f o r m
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