At least some games in the Arma series have also used a copy protection that messes with gameplay if it judged the game to be pirated. I don't know if it used tricks to trip crackers, though -- Wikipedia mentions intentional errors on optical media that didn't get passed on by disc copy software.
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Not DOS, but I remember playing a copy of Settlers III and was surprised when iron smelters produced pigs instead of iron.
That one was quite famous. Also the CD came with some sub-channel data, that only one program was able to copy. It had sheep on it but forgot its name
That must have been CloneCD then: https://en.m.wikipedia.org/wiki/CloneCD
At least some games in the Arma series have also used a copy protection that messes with gameplay if it judged the game to be pirated. I don't know if it used tricks to trip crackers, though -- Wikipedia mentions intentional errors on optical media that didn't get passed on by disc copy software.
https://en.wikipedia.org/wiki/FADE