Will it halt? (Cops)
Malbolge, 128 bytes, cracked by KBRON111

(=&amp;r:#o=~l4jz7g5vttbrpp^nllZjhhVfddRb`O;:('JYX#VV~jS{Ql&gt;jMKK9IGcFaD_X]\[ZYXWVsN6L4J\[kYEhVBeScba%_M]]~IYG3Eyx5432+rpp-n+l)j'h%B0


Have fun!

(Yes, I learned Malbolge just for this. Yes, it took an absurdly long time to finally get working. And yes, it was totally worth it.)

Wrapped, so you can see it in its full, er, "glory":

(=&amp;r:#o=~l4jz7g5vttbrpp^nllZjhhV
fddRb`O;:('JYX#VV~jS{Ql&gt;jMKK9IGc
FaD_X]\[ZYXWVsN6L4J\[kYEhVBeScba
%_M]]~IYG3Eyx5432+rpp-n+l)j'h%B0


I used this interpreter to test it; I'm not sure if it matters, but I figured I'd specify just in case.