Mimic, the Evil Script That Will Drive Programmers To Insanity (github.com)
JustAnotherOldGuy writes: Mimic implements a devilishly sick idea floated on Twitter by Peter Ritchie: "Replace a semicolon (;) with a Greek question mark (;) in your friend's C# code and watch them pull their hair out over the syntax error." There are quite a few characters in the Unicode character set that look, to some extent or another, like others – homoglyphs. Mimic substitutes common ASCII characters for obscure homoglyphs. Caution: using this script may get you fired and/or beaten to a pulp.
My students regularly copy-paste from an otherwise excellent source in which plain vertical double quotes have been auto-replaced with pretty slanted quotes. GCC complains about the illegal character on line XXX, I usually have to explain, and that's it. No hair-pulling involved, only git pulling.
This happens a lot with Russian programmers due to Latin C and Cyrillic Es homoglyphs that happen to be on the same key, and it's very easy to forget which keyboard layout is currently selected and type the wrong letter.